Identification of distinct active pools of yeast serine palmitoyltransferase in sub-compartments of the ER.

Sphingolipids (SPs) are one of the three major lipid classes in eukaryotic cells and serve as structural components of the plasma membrane. The rate-limiting step in SP biosynthesis is catalyzed by the serine palmitoyltransferase (SPT). In budding yeast (Saccharomyces cerevisiae), SPT is negatively regulated by the two proteins, Orm1 and Orm2. Regulating SPT activity enables cells to adapt SP metabolism to changing environmental conditions. Therefore, the Orm proteins are phosphorylated by two signaling pathways originating from either the plasma membrane or the lysosome (or vacuole in yeast). Moreover, uptake of exogenous serine is necessary for the regulation of SP biosynthesis, which suggests the existence of differentially regulated SPT pools based on their intracellular localization. However, measuring lipid metabolic enzyme activity in different cellular sub-compartments has been challenging. Combining a nanobody recruitment approach with SP flux analysis, we show that the nuclear endoplasmic reticulum (ER)-localized SPT and the peripheral ER localized SPT pools are differentially active. Thus, our data add another layer to the complex network of SPT regulation. Moreover, combining lipid metabolic enzyme re-localization with flux analysis serves as versatile tool to measure lipid metabolism with subcellular resolution.

Structure of the ceramide-bound SPOTS complex.

Sphingolipids are structural membrane components that also function in cellular stress responses. The serine palmitoyltransferase (SPT) catalyzes the rate-limiting step in sphingolipid biogenesis. Its activity is tightly regulated through multiple binding partners, including Tsc3, Orm proteins, ceramides, and the phosphatidylinositol-4-phosphate (PI4P) phosphatase Sac1. The structural organization and regulatory mechanisms of this complex are not yet understood. Here, we report the high-resolution cryo-EM structures of the yeast SPT in complex with Tsc3 and Orm1 (SPOT) as dimers and monomers and a monomeric complex further carrying Sac1 (SPOTS). In all complexes, the tight interaction of the downstream metabolite ceramide and Orm1 reveals the ceramide-dependent inhibition. Additionally, observation of ceramide and ergosterol binding suggests a co-regulation of sphingolipid biogenesis and sterol metabolism within the SPOTS complex.

Yeast Svf1 binds ceramides and contributes to sphingolipid metabolism at the ER cis-Golgi interface.

Ceramides are essential precursors of complex sphingolipids and act as potent signaling molecules. Ceramides are synthesized in the endoplasmic reticulum (ER) and receive their head-groups in the Golgi apparatus, yielding complex sphingolipids (SPs). Transport of ceramides between the ER and the Golgi is executed by the essential ceramide transport protein (CERT) in mammalian cells. However, yeast cells lack a CERT homolog, and the mechanism of ER to Golgi ceramide transport remains largely elusive. Here, we identified a role for yeast Svf1 in ceramide transport between the ER and the Golgi. Svf1 is dynamically targeted to membranes via an N-terminal amphipathic helix (AH). Svf1 binds ceramide via a hydrophobic binding pocket that is located in between two lipocalin domains. We showed that Svf1 membrane-targeting is important to maintain flux of ceramides into complex SPs. Together, our results show that Svf1 is a ceramide binding protein that contributes to sphingolipid metabolism at Golgi compartments.

Honey bees infer source location from the dances of returning foragers.

Honeybees (Apis mellifera carnica) communicate the direction and distance to a food source by means of a waggle dance. We ask whether bees recruited by the dance use it only as a flying instruction, with the technical form of a polar vector, or also translate it into a location vector that enables them to set courses directed toward the food source from arbitrary locations within their familiar territory. The flights of recruits captured on exiting the hive and released at distant sites were tracked by radar. The recruits performed first a straight flight in approximately the compass direction indicated by the dance. However, this "vector" portion of their flights and the ensuing tortuous "search" portion were strongly and differentially affected by the release site. Searches were biased toward the true location of the food and away from the location specified by translating the origin for the danced polar vector to the release site. We conclude that by following the dance recruits get two messages, a polar flying instruction (bearing and range from the hive) and a location vector that enables them to approach the source from anywhere in their familiar territory. The dance communication is much richer than thought so far.

Seroprevalence against Toscana virus in Spain: The case of the autonomous community of Madrid.

BACKGROUND & OBJECTIVES: The Toscana virus (TOSV) is a neurotropic arbovirus that is transmitted through the bite of some Phlebotomus species. In 2009, the largest outbreak of leishmaniasis described so far in Europe, occurred in the Autonomous Community of Madrid, Spain, which was related to the population increase of P. perniciosus in this region. METHODS: A seroprevalence study was conducted to determine the circulation of TOSV among the population of this geographic area. A total of 516 sera were collected in two different stages: 2007 (before the leishmaniasis outbreak) and 2018-19 (representative of the current situation). In the sera, presence of IgG antibodies against TOSV was determined by commercial ELISA. RESULTS: The overall seroprevalence was 34.5%. The anti-TOSV IgG level was significantly higher in the samples collected in 2007 (41.5%) than 2018-19 (27.3%). INTERPRETATION & CONCLUSION: The results of this study show a very active TOSV circulation in the region that is greater than expected. The lower seroprevalence figures in 2018-19 may be related to the vector and environmental control measures that were put in place as a result of the leishmaniasis outbreak of 2009. This highlights the importance of such strategies to reduce the incidence of TOSV infection and other vector-borne diseases.

Neprilysins regulate muscle contraction and heart function via cleavage of SERCA-inhibitory micropeptides.

Muscle contraction depends on strictly controlled Ca2+ transients within myocytes. A major player maintaining these transients is the sarcoplasmic/endoplasmic reticulum Ca2+ ATPase, SERCA. Activity of SERCA is regulated by binding of micropeptides and impaired expression or function of these peptides results in cardiomyopathy. To date, it is not known how homeostasis or turnover of the micropeptides is regulated. Herein, we find that the Drosophila endopeptidase Neprilysin 4 hydrolyzes SERCA-inhibitory Sarcolamban peptides in membranes of the sarcoplasmic reticulum, thereby ensuring proper regulation of SERCA. Cleavage is necessary and sufficient to maintain homeostasis and function of the micropeptides. Analyses on human Neprilysin, sarcolipin, and ventricular cardiomyocytes indicates that the regulatory mechanism is evolutionarily conserved. By identifying a neprilysin as essential regulator of SERCA activity and Ca2+ homeostasis in cardiomyocytes, these data contribute to a more comprehensive understanding of the complex mechanisms that control muscle contraction and heart function in health and disease.

Cvm1 is a component of multiple vacuolar contact sites required for sphingolipid homeostasis.

Membrane contact sites are specialized platforms formed between most organelles that enable them to exchange metabolites and influence the dynamics of each other. The yeast vacuole is a degradative organelle equivalent to the lysosome in higher eukaryotes with important roles in ion homeostasis and metabolism. Using a high-content microscopy screen, we identified Ymr160w (Cvm1, for contact of the vacuole membrane 1) as a novel component of three different contact sites of the vacuole: with the nuclear endoplasmic reticulum, the mitochondria, and the peroxisomes. At the vacuole-mitochondria contact site, Cvm1 acts as a tether independently of previously known tethers. We show that changes in Cvm1 levels affect sphingolipid homeostasis, altering the levels of multiple sphingolipid classes and the response of sphingolipid-sensing signaling pathways. Furthermore, the contact sites formed by Cvm1 are induced upon a decrease in sphingolipid levels. Altogether, our work identifies a novel protein that forms multiple contact sites and supports a role of lysosomal contacts in sphingolipid homeostasis.

Effectiveness of cell culture-based influenza vaccines compared with egg-based vaccines: What does the literature say? / Efectividad de la vacuna antigripal generada en cultivo celular frente a la producida en huevo: ¿Qué dice la literatura actual?

Introduction. Influenza vaccination is an effective wayof reducing the burden of seasonal influenza. Chicken eggembryos are the most common source of influenza vaccines,but cell culture production has emerged as an alternative thatcould be advantageous. This article reviews the available literature on the efficacy/effectiveness of cell culture-based influenza vaccines compared with egg-based vaccines.Methods. We conducted a review of the actual literatureand analyzed those studies comparing the effectiveness of cellculture-based and egg-based vaccines in the last ten years.Results. Eight studies were analyzed; 1 was a clinical trialand 7 were retrospective cohort studies. The clinical trial foundno significant differences in the efficacy of both vaccines withrespect to placebo. The results of the observational studieswere inconsistent and relative effectiveness varied amongstudies, even though most were performed during the sameseason, and in some cases, in the same region and using thesame data records. Furthermore, in most studies, the comparisons between vaccines were not statistically significant.Conclusions. There is insufficient evidence that cell culture-based vaccines are superior to egg-based vaccines interms of efficacy/effectiveness. (AU)

Introducción. La vacunación frente a la gripe es el método más efectivo para reducir el impacto de la gripe estacional.Los embriones de huevo de gallina son el método más comúnde fabricación de vacunas antigripales, pero la propagación encultivos celulares ha emergido como una alternativa que podría ofrecer alguna ventaja. El objetivo de este artículo es hacer una revisión de la literatura disponible sobre la efectividadde vacuna antigripal generada en cultivos celulares frente a lavacuna producida en huevo.Métodos. Se realizó una búsqueda bibliográfica de losestudios comparativos entre la vacuna propagada en cultivoscelulares y la producida en huevo con respecto a su efectividadpublicados en los últimos diez años.Resultados. De los siete estudios analizados, uno fue unensayo clínico y seis fueron estudios de cohortes retrospectivos. Los resultados del ensayo clínico mostraron que no existían diferencias significativas en cuanto a la eficacia de ambasvacunas. Con respecto a los estudios observacionales, los resultados fueron poco consistentes, con efectividades relativas quefueron muy diferentes entre estudios a pesar de que la mayoría se realizaron durante la misma temporada, y en algunosestudios, en la misma región y utilizando el mismo registro dedatos. Además, en la mayoría de los estudios no hubo significación estadística.Conclusiones. No existen evidencias suficientes de que lavacuna producida en cultivo celular sea superior a la generadaen huevo con respecto a su efectividad. (AU)

Burden of respiratory syncytial virus-associated lower respiratory infections in children in Spain from 2012 to 2018.

BACKGROUND: Respiratory syncytial virus (RSV) is a major cause of acute lower respiratory tract infection (ALRI) leading to infant hospitalization, morbidity and postnatal mortality in children younger than 5 years of age worldwide. The aim of this study was to collect data on hospitalizations for RSV-related ALRI in children in Spain from 2012 to 2018. METHODS: We used the discharge reports from the Minimum Basic Data Set (MBDS) to retrospectively analyze hospital discharge data in children ≤ 14 years of age with a diagnosis of acute lower respiratory tract infection, based on the ICD-9-CM and ICD-10-CM diagnosis codes, from 2012 to 2018. RESULTS: A total of 190,474 children, 58.1% boys and 41.9% girls, were admitted for lower respiratory tract infections in Spain, including 118,731 cases of bronchiolitis, 53,972 cases of bronchitis, 3710 cases of RSV-positive pneumonia, and 14,061 cases of RSV infections. Of these, 92,426 children (48.5%) had laboratory-confirmed RSV infection. The mean case fatality rate was almost 6 times higher for pneumonia (0.6%) than for bronchiolitis (0.1%) or bronchitis (0.1%). A significant linear increase in the mean annual hospitalization rate for pneumonia of almost 15% per year was found, with no changes in the trend over the study period. CONCLUSIONS: RSV-related respiratory infections remain a leading cause of infant hospitalization in Spain. Effective antiviral treatments and preventive vaccines are urgently needed for the management of RSV infection in children, especially for those aged 6 to 12 months.

Differential Association of Frailty and Sarcopenia With Mortality and Disability: Insight Supporting Clinical Subtypes of Frailty.

OBJECTIVES: Sarcopenia and frailty have been shown separately to predict disability and death in old age. Our aim was to determine if sarcopenia may modify the prognosis of frailty regarding both mortality and disability, raising the existence of clinical subtypes of frailty depending on the presence of sarcopenia. DESIGN: A Spanish longitudinal population-based study. SETTING AND PARTICIPANTS: The population consists of 1531 participants (>65 years of age) from the Toledo Study of Health Aging. METHODS: Sarcopenia and frailty were assessed following Foundation for the National Institutes of Health criteria and the Fried Frailty Phenotype, respectively. Mortality was assessed using the National Death Index. Functional status was determined using Katz index. We ran multivariate logistics and proportional hazards models adjusting for age, sex, baseline function, and comorbidities. RESULTS: Mean age was 75.4 years (SD 5.9). Overall, 70 participants were frail (4.6%), 565 prefrail (36.9%), and 435 sarcopenic (28.4%). Mean follow-up was 5.5 and 3.0 years for death and worsening function, respectively. Furthermore, 184 participants died (12%) and 324 worsened their functioning (24.8%). Frailty and prefrailty were associated with mortality and remained significant after adjustment by sarcopenia [hazard risk (HR) 3.09, 95% confidence interval (CI) 1.84-5.18; P < .001; HR 1.58, 95% CI 1.12-2.24, P = .01]. However, the association of sarcopenia with mortality was reduced and became nonsignificant (HR 1.43, 95% CI 0.99-2.07, P = .057) when both frailty and sarcopenia were included in the same model. In the disability model, frailty and sarcopenia showed a statistically significant interaction (P = .016): both had to be present to predict worsening of disability. CONCLUSIONS AND IMPLICATIONS: Sarcopenia plays a relevant role in the increased risk of functional impairment associated to frailty, but that seems not to be the case with mortality. This finding raises the need of assessing sarcopenia as a cornerstone of the clinical work after diagnosing frailty.

The yeast LYST homolog Bph1 is a Rab5 effector and prevents Atg8 lipidation at endosomes.

Lysosomes mediate degradation of macromolecules to their precursors for cellular recycling. Additionally, lysosome-related organelles mediate cell type-specific functions. Chédiak-Higashi syndrome is an autosomal, recessive disease, in which loss of the protein LYST causes defects in lysosomes and lysosome-related organelles. The molecular function of LYST, however, is largely unknown. Here, we dissected the function of the yeast LYST homolog, Bph1. We show that Bph1 is an endosomal protein and an effector of the minor Rab5 isoform Ypt52. Strikingly, bph1Δ mutant cells have lipidated Atg8 on their endosomes, which is sorted via late endosomes into the vacuole lumen under non-autophagy-inducing conditions. In agreement with this, proteomic analysis of bph1Δ vacuoles reveals an accumulation of Atg8, reduced flux via selective autophagy, and defective endocytosis. Additionally, bph1Δ cells have reduced autophagic flux under starvation conditions. Our observations suggest that Bph1 is a novel Rab5 effector that maintains endosomal functioning. When Bph1 is lost, Atg8 is lipidated at endosomes even during normal growth and ends up in the vacuole lumen. Thus, our results contribute to the understanding of the role of LYST-related proteins and associated diseases.

A lysosomal biogenesis map reveals the cargo spectrum of yeast vacuolar protein targeting pathways.

The lysosome is the major catabolic organelle in the cell that has been established as a key metabolic signaling center. Mutations in many lysosomal proteins have catastrophic effects and cause neurodegeneration, cancer, and age-related diseases. The vacuole is the lysosomal analog of Saccharomyces cerevisiae that harbors many evolutionary conserved proteins. Proteins reach vacuoles via the Vps10-dependent endosomal vacuolar protein sorting pathway, via the alkaline phosphatase (ALP or AP-3) pathway, and via the cytosol-to-vacuole transport (CVT) pathway. A systematic understanding of the cargo spectrum of each pathway is completely lacking. Here, we use quantitative proteomics of purified vacuoles to generate the yeast lysosomal biogenesis map. This dataset harbors information on the cargo-receptor relationship of almost all vacuolar proteins. We map binding motifs of Vps10 and the AP-3 complex and identify a novel cargo of the CVT pathway under nutrient-rich conditions. Our data show how organelle purification and quantitative proteomics can uncover fundamental insights into organelle biogenesis.

Low membrane fluidity triggers lipid phase separation and protein segregation in living bacteria.

All living organisms adapt their membrane lipid composition in response to changes in their environment or diet. These conserved membrane-adaptive processes have been studied extensively. However, key concepts of membrane biology linked to regulation of lipid composition including homeoviscous adaptation maintaining stable levels of membrane fluidity, and gel-fluid phase separation resulting in domain formation, heavily rely upon in vitro studies with model membranes or lipid extracts. Using the bacterial model organisms Escherichia coli and Bacillus subtilis, we now show that inadequate in vivo membrane fluidity interferes with essential complex cellular processes including cytokinesis, envelope expansion, chromosome replication/segregation and maintenance of membrane potential. Furthermore, we demonstrate that very low membrane fluidity is indeed capable of triggering large-scale lipid phase separation and protein segregation in intact, protein-crowded membranes of living cells; a process that coincides with the minimal level of fluidity capable of supporting growth. Importantly, the in vivo lipid phase separation is not associated with a breakdown of the membrane diffusion barrier function, thus explaining why the phase separation process induced by low fluidity is biologically reversible.

Burden of severe bronchiolitis in children up to 2 years of age in Spain from 2012 to 2017.

Bronchiolitis represents a heavy burden of disease in children under 2 years of age in our society due to the high infectivity of the Respiratory Syncytial Virus [RSV] and the vulnerability of the youngest children.The objective of this retrospective epidemiological study was to show the burden of severe bronchiolitis in Spain through population-based estimates of hospitalizations due to bronchiolitis in children up to 24 months old during a 6-year period (2012-2017).A total of 100,115 cases of bronchiolitis required hospitalization in Spain from 2012 to 2017. Most cases of bronchiolitis that required hospitalization were in infants under 3 months of age. The hospitalization rate for bronchiolitis for children under 1 year of age was 3,838.27 per 100,000 healthy children. During the 6-year study period, a total of 82 deaths due to bronchiolitis were reported among hospitalized infants. Among these deaths, more than 50% were in patients younger than 3 months of age. The annual average cost to the National Health Care System was €58 M, with a mean hospitalization cost of €3,512 per case.

Prognostic factors and combined use of tocilizumab and corticosteroids in a Spanish cohort of elderly COVID-19 patients.

Coronavirus disease 2019 (COVID-19) infection in elderly patients is more aggressive and treatments have shown limited efficacy. Our objective is to describe the clinical course and to analyze the prognostic factors associated with a higher risk of mortality of a cohort of patients older than 80 years. In addition, we assess the efficacy of immunosuppressive treatments in this population. We analyzed the data from 163 patients older than 80 years admitted to our institution for COVID-19, during March and April 2020. A Lasso regression model and subsequent multivariate Cox regression were performed to select variables predictive of death. We evaluated the efficacy of immunomodulatory therapy in three cohorts using adjusted survival analysis. The mortality rate was 43%. The mean age was 85.2 years. The disease was considered severe in 76.1% of the cases. Lasso regression and multivariate Cox regression indicated that factors correlated with hospital mortality were: age (hazard ratio [HR] 1.12, 95% confidence interval [CI]: 1.03-1.22), alcohol consumption (HR 3.15, 95% CI: 1.27-7.84), CRP > 10 mg/dL (HR 2.67, 95% CI: 1.36-5.24), and oxygen support with Venturi Mask (HR 6.37, 95% CI: 2.18-18.62) or reservoir (HR 7.87, 95% CI: 3.37-18.38). Previous treatment with antiplatelets was the only protective factor (HR 0.47, 95% CI: 0.23-0.96). In the adjusted treatment efficacy analysis, we found benefit in the combined use of tocilizumab (TCZ) and corticosteroids (CS) (HR 0.09, 95% CI: 0.01-0.74) compared to standard treatment, with no benefit of CS alone (HR 0.95, 95% CI: 0.53-1.71). Hospitalized elderly patients suffer from a severe and often fatal form of COVID-19 disease. In this regard, several parameters might identify high-risk patients upon admission. Combined use of TCZ and CS could improve survival.

Impact of Penicillin Allergy Label on Length of Stay and Mortality in Hospitalized Patients through a Clinical Administrative National Dataset.

BACKGROUND: Penicillin allergy is a common problem in the management of infectious diseases. The aim of this study was to determine the impact of penicillin allergy on length of hospital stay (LOHS) among hospitalized adult patients and on in-hospital mortality at a national level. METHODS: A retrospective cohort study of adult patients discharged from the Spanish Hospital System between 2006 and 2015 was conducted using the Minimum Basic Data Set (MBDS). We compared LOHS and in-hospital mortality of adult patients whose records contained penicillin allergy code V14.0 (International Classification of Diseases, Ninth Revision, Clinical Modification) as a secondary diagnosis, with a random sample without such a code. RESULTS: We identified 981,291 admissions with code V14.0, which corresponded to 2.63% of all hospitalizations. Adults patients with a penicillin allergy label were significantly older than patients without such a label, with a median of 70 years (interquartile range [IQR]: 51-80) versus 63 years (IQR: 40-77). The proportion of women and the prevalence of infectious diseases were higher in the group with a penicillin allergy label (61.40% vs. 53.84%; 34.04% vs. 30.01%; respectively). We found a higher median Elixhauser-Van Walraven score in hospitalized patients with an allergy label. The median LOHS for hospitalizations with a penicillin allergy label (5 [IQR: 2-9]) was significantly longer than that in those without such a label (4 [IQR: 2-9]). Multivariate analysis showed an increase in LOHS due to the penicillin allergy label (odds ratio [OR] [95% confidence interval [CI]: 1.061 [1.057-1.065]) and a decrease in mortality in penicillin allergy records (OR [95% CI]: 0.834 [0.825-0.844]). CONCLUSION: In our study, the prevalence of a penicillin allergy label in hospitalized patients, using the MBDS, is low. Hospitalizations with an allergy label was associated with a longer LOHS. However, penicillin-allergic patients did not show higher mortality rates. Inaccurate reporting of penicillin allergies may have an impact on healthcare resources.

Explaining the Variance in Cardiovascular Disease Risk Factors: A Comparison of Demographic, Socioeconomic, and Genetic Predictors.

BACKGROUND: Efforts to explain the burden of cardiovascular disease (CVD) often focus on genetic factors or social determinants of health. There is little evidence on the comparative predictive value of each, which could guide clinical and public health investments in measuring genetic versus social information. We compared the variance in CVD-related outcomes explained by genetic versus socioeconomic predictors. METHODS: Data were drawn from the Health and Retirement Study (N = 8,720). We examined self-reported diabetes, heart disease, depression, smoking, and body mass index, and objectively measured total and high-density lipoprotein cholesterol. For each outcome, we compared the variance explained by demographic characteristics, socioeconomic position (SEP), and genetic characteristics including a polygenic score for each outcome and principal components (PCs) for genetic ancestry. We used R-squared values derived from race-stratified multivariable linear regressions to evaluate the variance explained. RESULTS: The variance explained by models including all predictors ranged from 3.7% to 14.3%. Demographic characteristics explained more than half this variance for most outcomes. SEP explained comparable or greater variance relative to the combination of the polygenic score and PCs for most conditions among both white and Black participants. The combination of SEP, polygenic score, and PCs performed substantially better, suggesting that each set of characteristics may independently contribute to the prediction of CVD-related outcomes. Philip R. Lee Institute for Health Policy Studies, Department of Family & Community Medicine, UCSF. CONCLUSIONS: Focusing on genetic inputs into personalized medicine predictive models, without considering measures of social context that have clear predictive value, needlessly ignores relevant information that is more feasible and affordable to collect on patients in clinical settings. See video abstract at, http://links.lww.com/EDE/B879.

Hospitalizations related to meningococcal infection in Spain from 1997 to 2018.

BACKGROUND: Baseline hospitalization, mortality, and in-hospital fatality rates for meningococcal infection are required to evaluate preventive interventions, such as the inclusion of the conjugated quadrivalent meningococcal vaccine and serogroup B based protein vaccines. METHODS: All meningococcal infection-related hospitalizations in any diagnostic position in Spain from 1st January 1997 through 31st December 2018 were analysed. The annual hospitalization rate, mortality rate and case-fatality rate were calculated. RESULTS: The average hospitalization rate for meningococcal infection was 1.64 (95% CI 1.61 to 1.66) hospitalizations per 100,000 inhabitants during the study period and significantly decreased from 1997 to 2018. Hospitalizations for meningococcal infection decreased significantly with age and were concentrated in children under 5 years of age (46%). The hospitalization rates reached 29 per 100,000 and 24 per 100,000 children under 1 and 2 years of age, respectively. The in-hospital case-fatality rate was 7.45% (95% CI 7.03 to 7.86). Thirty percent of the deaths occurred in children under 5 years of age, and more than half occurred in adults. The case fatality rate increased significantly with age (p < 0.001). CONCLUSION: It is necessary to maintain epidemiological surveillance of meningococcal infection to determine the main circulating serogroups involved, track their evolution, and evaluate preventive measures whose effectiveness must be assessed in all age groups.

Subunit exchange among endolysosomal tethering complexes is linked to contact site formation at the vacuole.

The hexameric HOPS (homotypic fusion and protein sorting) complex is a conserved tethering complex at the lysosome-like vacuole, where it mediates tethering and promotes all fusion events involving this organelle. The Vps39 subunit of this complex also engages in a membrane contact site between the vacuole and the mitochondria, called vCLAMP. Additionally, four subunits of HOPS are also part of the endosomal CORVET tethering complex. Here, we analyzed the partition of HOPS and CORVET subunits between the different complexes by tracing their localization and function. We find that Vps39 has a specific role in vCLAMP formation beyond tethering, and that vCLAMPs and HOPS compete for the same pool of Vps39. In agreement, we find that the CORVET subunit Vps3 can take the position of Vps39 in HOPS. This endogenous pool of a Vps3-hybrid complex is affected by Vps3 or Vps39 levels, suggesting that HOPS and CORVET assembly is dynamic. Our data shed light on how individual subunits of tethering complexes such as Vps39 can participate in other functions, while maintaining the remaining subcomplex available for its function in tethering and fusion.

Burden of pneumonia in patients with viral and bacterial coinfection in Spain during six consecutive influenza seasons, from 2009-10 to 2014-15.

PURPOSE: Lower respiratory infections remain the most lethal communicable disease worldwide. Viral and bacterial coinfections (VBC) are common complications in patients with seasonal influenza and are associated with around 25% of all influenza-related deaths. The burden of pneumonia in patients with VBC in Spain is poorly characterized. To address this question, we aimed to provide population data over a period of six consecutive influenza seasons, from 2009-10 to 2014-15. METHODS: We used the discharge report from the Minimum Basic Data Set (MBDS), published annually by the Spanish Ministry of Health, to retrospectively analyse hospital discharge data in individuals aged ≥60 years with a diagnosis of pneumonia and influenza, based on the International Classification of Diseases (ICD-9-CM codes 480-486 and 487-488, respectively), from 1 October 2009 to 30 September 2015. RESULTS: In total, 1933 patients ≥60 years old were hospitalized for pneumonia and influenza, of whom 55.2% were male. The median age was 74 years (interquartile range [IRQ] 15); half of the patients were ≥75 years old. Influenza was the main diagnosis in 64.4% of the patients, and all-cause pneumonia in 15.8%, half of whom were assigned a diagnostic code for pneumococcal pneumonia. The mean annual hospitalization rate was 2.99 per 100,000 population (95% CI 2.9-3.1) throughout the study period, while the highest rate, 5.6 per 100,000 population (95% CI 5.2-6.0), was observed in the 2013-14 season. The mean annual mortality rate was 0.5 deaths per 100,000 population (95% CI 0.4-0.6) and in-hospital case fatality rate was 16.1% (95% CI 14.5-17.8). CONCLUSIONS: In Spain, community-acquired pneumonia and influenza continue to be an important cause of hospitalization and mortality in patients over 60 years of age. There is an urgent need to further develop prevention strategies such as joint vaccination for both pathologies.