Adjuvant Therapy of Nivolumab Combined With Ipilimumab Versus Nivolumab Alone in Patients With Resected Stage IIIB-D or Stage IV Melanoma (CheckMate 915).

PURPOSE: Ipilimumab and nivolumab have each shown treatment benefit for high-risk resected melanoma. The phase III CheckMate 915 trial evaluated adjuvant nivolumab plus ipilimumab versus nivolumab alone in patients with resected stage IIIB-D or IV melanoma. PATIENTS AND METHODS: In this randomized, double-blind, phase III trial, 1,833 patients received nivolumab 240 mg once every 2 weeks plus ipilimumab 1 mg/kg once every 6 weeks (916 patients) or nivolumab 480 mg once every 4 weeks (917 patients) for ≤ 1 year. After random assignment, patients were stratified by tumor programmed death ligand 1 (PD-L1) expression and stage. Dual primary end points were recurrence-free survival (RFS) in randomly assigned patients and in the tumor PD-L1 expression-level < 1% subgroup. RESULTS: At a minimum follow-up of approximately 23.7 months, there was no significant difference between treatment groups for RFS in the all-randomly assigned patient population (hazard ratio, 0.92; 95% CI, 0.77 to 1.09; P = .269) or in patients with PD-L1 expression < 1% (hazard ratio, 0.91; 95% CI, 0.73 to 1.14). In all patients, 24-month RFS rates were 64.6% (combination) and 63.2% (nivolumab). Treatment-related grade 3 or 4 adverse events were reported in 32.6% of patients in the combination group and 12.8% in the nivolumab group. Treatment-related deaths were reported in 0.4% of patients in the combination group and in no nivolumab-treated patients. CONCLUSION: Nivolumab 240 mg once every 2 weeks plus ipilimumab 1 mg/kg once every 6 weeks did not improve RFS versus nivolumab 480 mg once every 4 weeks in patients with stage IIIB-D or stage IV melanoma. Nivolumab showed efficacy consistent with previous adjuvant studies in a population resembling current practice using American Joint Committee on Cancer eighth edition, reaffirming nivolumab as a standard of care for melanoma adjuvant treatment.

Long-Term Outcomes With Nivolumab Plus Ipilimumab or Nivolumab Alone Versus Ipilimumab in Patients With Advanced Melanoma.

PURPOSE: In the phase III CheckMate 067 trial, durable clinical benefit was demonstrated previously with nivolumab plus ipilimumab and nivolumab alone versus ipilimumab. Here, we report 6.5-year efficacy and safety outcomes. PATIENTS AND METHODS: Patients with previously untreated unresectable stage III or stage IV melanoma were randomly assigned 1:1:1 to receive nivolumab 1 mg/kg plus ipilimumab 3 mg/kg once every 3 weeks (four doses) followed by nivolumab 3 mg/kg once every 2 weeks (n = 314), nivolumab 3 mg/kg once every 2 weeks (n = 316), or ipilimumab 3 mg/kg once every 3 weeks (four doses; n = 315). Coprimary end points were progression-free survival and overall survival (OS) with nivolumab plus ipilimumab or nivolumab versus ipilimumab. Secondary end points included objective response rate, descriptive efficacy assessments of nivolumab plus ipilimumab versus nivolumab alone, and safety. Melanoma-specific survival (MSS; descriptive analysis), which excludes deaths unrelated to melanoma, was also evaluated. RESULTS: Median OS (minimum follow-up, 6.5 years) was 72.1, 36.9, and 19.9 months in the combination, nivolumab, and ipilimumab groups, respectively. Median MSS was not reached, 58.7, and 21.9 months, respectively; 6.5-year OS rates were 57%, 43%, and 25% in patients with BRAF-mutant tumors and 46%, 42%, and 22% in those with BRAF-wild-type tumors, respectively. In patients who discontinued treatment, the median treatment-free interval was 27.6, 2.3, and 1.9 months, respectively. Since the 5-year analysis, no new safety signals were observed. CONCLUSION: These 6.5-year CheckMate 067 results, which include the longest median OS in a phase III melanoma trial reported to date and the first report of MSS, showed durable, improved clinical outcomes with nivolumab plus ipilimumab or nivolumab versus ipilimumab in patients with advanced melanoma and, in descriptive analyses, with the combination over nivolumab monotherapy.

Characteristics and Outcomes of Psychiatric Inpatients With Severe Mental Illness and COVID-19: Experience From a COVID-19-Specific Acute Psychiatric Ward in Istanbul.

ABSTRACT: Recent studies indicated that psychiatric inpatients with severe mental illness (SMI) are at a greater risk of morbidity and mortality from COVID-19. However, there is still little data about the impact of comorbid COVID-19 infection on the course and outcome of acute exacerbations in this population. We conducted a prospective historically matched case control study. The sociodemographic and clinical characteristics of acute psychiatric inpatients with SMI and comorbid COVID-19 (n = 21) were compared with those of historically-matched non-COVID-19 controls with SMI (n = 42). The outcomes for acute inpatients with SMI and COVID-19 were also investigated. The new-onset SMI rate was relatively higher (23.8%) in the COVID-19 group, which has characteristics similar to those of the non-COVID-19 group except for working status (p < 0.05). The COVID-19 group had a high rate of relapse (47.6%) within 6 months of discharge. Our study suggests that patients with SMI who contracted SARS-CoV-2 may have a higher rate of new-onset mental disorder. Considering the high rate of relapse during the pandemic, chronically ill patients with SMI and COVID-19 should be closely monitored after discharge.

An Observational Retrospective Study Investigating Changes in Seizure Adequacy Parameters of Electroconvulsive Therapy and Their Relationships to Clinical Outcome in Schizophrenia and Schizoaffective Disorder.

The aim of the current study was to investigate a possible relationship between electroconvulsive therapy (ECT) seizure adequacy parameters and clinical outcome as well as differences between ECT responders and nonresponders in terms of ECT seizure parameters in patients diagnosed with schizophrenia and schizoaffective disorder. First and last ECT records data, sociodemographic variables, and baseline and post ECT Positive and Negative Syndrome Scale scores were obtained. Maximum sustained power was higher in last ECT in favor of responders while peak heart rate was higher in ECT nonresponders than responders in first ECT. Stimulus doses were higher in last ECT than in the first ECT in both groups. No predictor variable was observed among baseline ECT seizure parameters for clinical improvement. Study was insufficient to yield a precise finding pointing a relationship between electrophysiological seizure parameters and clinical outcome in schizophrenia and schizoaffective disorder.

Adverse drug reactions associated with concurrent acute psychiatric treatment and Covid-19 drug therapy.

OBJECTIVE: Psychiatric patients are at increased risk of contamination, morbidity, and mortality associated with COVID-19, together with potentially more pronounced adverse effects. We present and discuss the adverse effects observed in an acute psychiatric clinic that has admitted COVID-19 patients during the first three months of the pandemic in Turkey. METHODS: The COVID-19 treatment schemes were formed in accordance with the national and regional guidelines at the time of admittance, which were mainly based on the use of hydroxychloroquine and other drugs. The sample consisted exclusively of inpatients, and all patients were enrolled in the study regardless of their specific diagnosis or treatment schemes. RESULTS: 4 out of 23 patients (17.4%) had experienced adverse effects, two of which had mild hepatic enzyme elevation and one had mild sinus bradycardia. Of note is that we haven't encountered any serious complications or life-threatening events during inpatient treatment. The most emphasised adverse effect in the literature, namely QTc prolongation and ECG changes, were not observed in our sample. The adverse effects were not found to be significantly associated with patient-related factors nor dose of antipsychotic medication. CONCLUSIONS: From our point of view, non-cardiac adverse effects should not be overlooked while treating comorbid psychiatric and COVID-19 patients.KEY POINTSAcute inpatient psychiatric treatment of patients who have comorbid COVID-19 is a complex situation requiring multidisciplinary action.Adverse drug reactions, which may or not result from the interaction of psychiatric and COVID-19 treatment, should be of concern for this patient group.While there is controversy over the benefits of some of the off-label COVID-19 medications, there should also be discussion over safety and concomitant medication use.In order to be adequately prepared for future escalations of COVID-19 pandemic, psychiatric services should thoroughly evaluate their initial experience with COVID-19, including from the point of drug effectiveness and safety.

Psychiatric comorbidity and temperament-character traits of the patients with lichen simplex chronicus: The relation with the symptom severity of the disease.

The aim of this study is to evaluate psychiatric comorbidity, temperament and character traits, depression and anxiety levels, and their relation with symptom severity in patients with lichen simplex chronicus (LSC). About 50 patients with LSC were enrolled in the study along with 49 controls. The Structured Clinical Interview for DSM-5 (SCID-5), Temperament and Character Inventory (TCI), Beck Anxiety Inventory (BAI), and Beck Depression Inventory (BDI) were administered to all subjects for psychiatric assessment. Skindex-16 symptom scale was performed for assessing the symptom severity of LSC. LSC group were showing an incidence of 62% in terms of psychiatric comorbidity and 14% of them had two psychiatric diagnoses. The most common psychiatric disorders were major depressive disorder (32%), dysthymia (18%), and generalized anxiety disorder (12%). LSC group had significantly higher mean BDI (18.60 ± 11.77 vs 7.40 ± 4.90) and BAI scores (18.56 ± 13.75 vs 5.18 ± 5.34) than the control group. Patients with LSC displayed higher scores in Harm Avoidance Dimension (19.74 ± 5.18 vs 15.00 ± 5.13) of temperament and regarding character dimensions, they had lower scores in self-directedness (25.52 ± 6.69 vs 29.51 ± 5.54). When analysis of covariance (ANCOVA) was performed while BDI and BAI scores were taken as covariates cooperativeness became significantly higher in the LSC group. Patients with LSC had a high incidence of psychiatric comorbidity, significantly higher depression and anxiety levels, and differed from control group in terms of TCI profile and these conditions were related to symptom severity of the LSC. Comorbid psychiatric conditions and personality traits should be considered as crucial factors for the effective treatment of LSC.

A Randomized, Placebo-Controlled Trial of Pembrolizumab Plus Chemotherapy in Patients With Metastatic Squamous NSCLC: Protocol-Specified Final Analysis of KEYNOTE-407.

INTRODUCTION: In the randomized KEYNOTE-407 study (ClinicalTrials.gov, NCT02775435), pembrolizumab plus carboplatin and paclitaxel/nab-paclitaxel (chemotherapy) significantly improved overall survival (OS) and progression-free survival (PFS) compared with placebo plus chemotherapy in patients with previously untreated metastatic squamous NSCLC. We report updated efficacy outcomes from the protocol-specified final analysis and, for the first time, progression on next line of treatment. METHODS: Eligible patients were randomized to chemotherapy plus either pembrolizumab (n = 278) or placebo (n = 281). After positive results from the second interim analysis, patients still receiving placebo could cross over to pembrolizumab monotherapy at the time of confirmed progressive disease. The primary end points were OS and PFS. PFS-2 (time from randomization to progression on next-line treatment/death, whichever occurred first) was an exploratory end point. RESULTS: After median (range) follow-up of 14.3 (0.1-31.3) months, pembrolizumab plus chemotherapy continued to exhibit a clinically meaningful improvement over placebo plus chemotherapy in OS (median, 17.1 mo [95% confidence interval (CI): 14.4‒19.9] versus 11.6 mo [95% CI: 10.1‒13.7]; hazard ratio [HR], 0.71 [95% CI: 0.58‒0.88]) and PFS (median, 8.0 mo [95% CI: 6.3‒8.4] versus 5.1 mo [95% CI: 4.3‒6.0]; HR, 0.57 [95% CI: 0.47‒0.69]). PFS-2 was longer for patients randomized to first-line pembrolizumab plus chemotherapy (HR, 0.59 [95% CI: 0.49‒0.72]). Grade 3 to 5 adverse events occurred in 74.1% and 69.6% of patients receiving pembrolizumab plus chemotherapy and placebo plus chemotherapy, respectively. CONCLUSIONS: Pembrolizumab plus chemotherapy continued to exhibit substantially improved OS and PFS in patients with metastatic squamous NSCLC. The PFS-2 outcomes support pembrolizumab plus chemotherapy as a standard first-line treatment in patients with metastatic squamous NSCLC.

Updated Analysis From KEYNOTE-189: Pembrolizumab or Placebo Plus Pemetrexed and Platinum for Previously Untreated Metastatic Nonsquamous Non-Small-Cell Lung Cancer.

PURPOSE: In KEYNOTE-189, first-line pembrolizumab plus pemetrexed-platinum significantly improved overall survival (OS) and progression-free survival (PFS) compared with placebo plus pemetrexed-platinum in patients with metastatic nonsquamous non‒small-cell lung cancer (NSCLC), irrespective of tumor programmed death-ligand 1 (PD-L1) expression. We report an updated analysis from KEYNOTE-189 (ClinicalTrials.gov: NCT02578680). METHODS: Patients were randomly assigned (2:1) to receive pemetrexed and platinum plus pembrolizumab (n = 410) or placebo (n = 206) every 3 weeks for 4 cycles, then pemetrexed maintenance plus pembrolizumab or placebo for up to a total of 35 cycles. Eligible patients with disease progression in the placebo-combination group could cross over to pembrolizumab monotherapy. Response was assessed per RECIST (version 1.1) by central review. No alpha was assigned to this updated analysis. RESULTS: As of September 21, 2018 (median follow-up, 23.1 months), the updated median (95% CI) OS was 22.0 (19.5 to 25.2) months in the pembrolizumab-combination group versus 10.7 (8.7 to 13.6) months in the placebo-combination group (hazard ratio [HR], 0.56; 95% CI, 0.45 to 0.70]). Median (95% CI) PFS was 9.0 (8.1 to 9.9) months and 4.9 (4.7 to 5.5) months, respectively (HR, 0.48; 95% CI, 0.40 to 0.58). Median (95% CI) time from randomization to objective tumor progression on next-line treatment or death from any cause, whichever occurred first (progression-free-survival-2; PFS-2) was 17.0 (15.1 to 19.4) months and 9.0 (7.6 to 10.4) months, respectively (HR, 0.49; 95% CI, 0.40 to 0.59). OS and PFS benefits with pembrolizumab were observed regardless of PD-L1 expression or presence of liver/brain metastases. Incidence of grade 3-5 adverse events was similar in the pembrolizumab-combination (71.9%) and placebo-combination (66.8%) groups. CONCLUSION: First-line pembrolizumab plus pemetrexed-platinum continued to demonstrate substantially improved OS and PFS in metastatic nonsquamous NSCLC, regardless of PD-L1 expression or liver/brain metastases, with manageable safety and tolerability.

Cognitive Psychophysiological Substrates of Affective Temperaments.

Affective temperaments are the subclinical manifestations or phenotypes of mood states and hypothetically represent one healthy end of the mood disorder spectrum. However, there is a scarcity of studies investigating the neurobiological basis of affective temperaments. One fundamental aspect of temperament is the behavioral reactivity to environmental stimuli, which can be effectively evaluated by use of cognitive event-related potentials (ERPs) reflecting the diversity of information processing. The aim of the present study is to explore the associations between P300 and the affective temperamental traits in healthy individuals. We recorded the P300 ERP waves using an auditory oddball paradigm in 50 medical student volunteers (23 females, 27 males). Participants' affective temperaments were evaluated using the Temperament Evaluation of Memphis, Pisa, Paris, and San Diego-auto questionnaire version (TEMPS-A). In bivariate analyses, depressive temperament score was significantly correlated with P300 latency ( rs = 0.37, P < .01). In a multiple linear regression analysis, P300 latency showed a significant positive correlation with scores of depressive temperament (ß = 0.40, P < .01) and a significant negative one with scores of cyclothymic temperament (ß = -0.29, P = .03). Affective temperament scores were not associated with P300 amplitude and reaction times. These results indicate that affective temperaments are related to information processing in the brain. Depressive temperament may be characterized by decreased physiological arousal and slower information processing, while the opposite was observed for cyclothymic temperament.

Level of serum thioredoxin and correlation with neurocognitive functions in patients with schizophrenia using clozapine and other atypical antipsychotics.

Thioredoxin is a serum antioxidant that has been investigated in the etiology of schizophrenia. The aim of this study is investigating the relationship between serum thioredoxin levels and cognitive functions in acute psychotic episode and remission state patients with schizophrenia; and examining whether there were differences between patients using clozapine and other atypical antipsychotics; including risperidone, olanzapine and amisulpride. This research was performed in schizophrenia patients hospitalized with acute psychotic episode (n=57), reevaluated patients after the initiation of treatment (mean 16 weeks) (n=46), and healthy controls (n=41). Positive and Negative Syndrome Scale, Clinic Global Impressions Scale, Neuropsychologic test battery to assess cognitive performance, and serum thioredoxin levels measured by ELISA were used in this research. Serum thioredoxin levels were highest in acute psychotic episode, lower in the remission state and the lowest in healthy controls. Significant correlation has been established between serum thioredoxin levels and Trail Making Test-A performance in remission state patients. In conclusion, serum thioredoxin levels were increased in acute psychotic episode and decreased in remission state, and its relationship with attention is worth to consider in schizophrenia patients.

Concise review: the role of oxygen in hematopoietic stem cell physiology.

Molecular dioxygen, O(2), is an important element in cellular microenvironment in vivo, and often overlooked in standard in vitro and ex vivo cell culture systems. Molecular oxygen is the ultimate electron acceptor in oxidative cellular respiration, and also a signal that regulates cell fate through concentration gradients. Recent advances in physiology of oxygen and adult stem cell research have shown that apart from being important for oxidative phosphorylation, thus energy metabolism, oxygen is also important as a signaling molecule and an integral part of the stem cell niche. This review article covers the influence of physiologically relevant oxygen levels on adult stem cells through highlighting the research on the effect of oxygen concentration on hematopoietic stem cell maintenance, proliferation and differentiation. This is important particularly to understand the embryonic and adult stem cell biology and physiology. The new discoveries in this field will help to further improve current tissue engineering and clinical applications. In addition, understanding the relationship between oxygen and stemness is invaluable for the advanced treatments of neoplastic diseases. Authors believe that in the future, active and programmed dynamic of oxygen levels will be routinely used for the programmed in vitro and ex vivo expansion of different adult stem cell types and tissue regeneration purposes.

Affective temperaments in subjects with female-to-male gender dysphoria.

BACKGROUND: Males and females have different temperaments. In individuals with gender dysphoria (GD) there is marked incongruence between a person׳s expressed/experienced gender and their biological sex. The present study aimed to investigate the most common affective temperaments in individuals with female-to-male (FtM) GD. METHODS: We performed a prospective and comparative study investigating affective temperaments in subjects with FtM GD. Eighty subjects with FtM GD and 68 female controls were enrolled. The Temperament Evaluation of Memphis, Pisa, Paris and San Diego Autoquestionnaire (TEMPS-A) was completed by all participants. RESULTS: TEMPS-A scores were significantly higher in subjects with FtM GD for hyperthymic temperament (p≤0.001), whereas depressive (p≤0.001), anxious (p≤0.001), and cyclothymic (p=0.028) temperament scores were significantly higher in female controls. LIMITATIONS: The study was limited by the lack of male-to-female subjects and male controls. CONCLUSIONS: The results of our study indicate that individuals with FtM GD have significantly higher scores of hyperthymic temperament, measured by TEMPS-A. Biological basis underlying the development of gender identity independent from the biological sex might be related with affective temperaments.

The impact of cognitive impairment, neurological soft signs and subdepressive symptoms on functional outcome in bipolar disorder.

BACKGROUND: Cognitive impairments and subsyndromal depressive symptoms are present during euthymic periods of bipolar disorder (BD). Most studies have determined that cognitive impairments and residual depressive symptoms have major impacts on psychosocial functioning. The aim of the present study was to identify the major factor responsible for low psychosocial functioning in a subgroup of patients with BD despite clinical recovery. METHODS: Sixty patients with bipolar I disorder and 41 healthy subjects were enrolled in this study. Cognitive performance, neurological soft signs (NSSs), psychosocial functioning, residual mood symptoms and illness characteristics were assessed. Using the median value of the Functioning Assessment Short Test (FAST) as the cut-off point, the patients were divided into two groups, high- (n=29) or low-functioning (n=31), and they were compared based on total NSS, residual depressive symptoms, cognitive performance and clinical variables. RESULTS: Performances on the verbal memory tests and social functioning were significantly worse in the euthymic patients with BD. Increased rates of NSS were identified in the patients compared with the normal controls. The low-functioning patients performed significantly worse on verbal memory, and their NSS and residual depressive symptoms were significantly higher compared to high-functioning patients. In the regression analysis, subsyndromal depressive symptoms and verbal learning measures were identified as the best predictors of psychosocial functioning. LIMITATIONS: The patients were artificially separated into two groups based on a FAST score cut-off. CONCLUSIONS: In this study, residual depressive symptoms and verbal memory impairments were the most prominent factors associated with the level of functioning.

Real time analysis of metabolic profile in ex vivo mouse intestinal crypt organoid cultures.

The small intestinal mucosa exhibits a repetitive architecture organized into two fundamental structures: villi, projecting into the intestinal lumen and composed of mature enterocytes, goblet cells and enteroendocrine cells; and crypts, residing proximal to the submucosa and the muscularis, harboring adult stem and progenitor cells and mature Paneth cells, as well as stromal and immune cells of the crypt microenvironment. Until the last few years, in vitro studies of small intestine was limited to cell lines derived from either benign or malignant tumors, and did not represent the physiology of normal intestinal epithelia and the influence of the microenvironment in which they reside. Here, we demonstrate a method adapted from Sato et al. (2009) for culturing primary mouse intestinal crypt organoids derived from C57BL/6 mice. In addition, we present the use of crypt organoid cultures to assay the crypt metabolic profile in real time by measurement of basal oxygen consumption, glycolytic rate, ATP production and respiratory capacity. Organoids maintain properties defined by their source and retain aspects of their metabolic adaptation reflected by oxygen consumption and extracellular acidification rates. Real time metabolic studies in this crypt organoid culture system are a powerful tool to study crypt organoid energy metabolism, and how it can be modulated by nutritional and pharmacological factors.

The hazards of DAPI photoconversion: effects of dye, mounting media and fixative, and how to minimize the problem.

Immunocytochemistry is a powerful tool for detection and visualization of specific molecules in living or fixed cells, their localization and their relative abundance. One of the most commonly used fluorescent DNA dyes in immunocytochemistry applications is 4',6-diamidino-2-phenylindole dihydrochloride, known as DAPI. DAPI binds strongly to DNA and is used extensively for visualizing cell nuclei. It is excited by UV light and emits characteristic blue fluorescence. Here, we report a phenomenon based on an apparent photoconversion of DAPI that results in detection of a DAPI signal using a standard filter set for detection of green emission due to blue excitation. When a sample stained with DAPI only was first imaged with the green filter set (FITC/GFP), only a weak cytoplasmic autofluorescence was observed. Next, we imaged the sample with a DAPI filter set, obtaining a strong nuclear DAPI signal as expected. Upon reimaging the same samples with a FITC/GFP filter set, robust nuclear fluorescence was observed. We conclude that excitation with UV results in a photoconversion of DAPI that leads to detection of DAPI due to excitation and emission in the FITC/GFP channel. This phenomenon can affect data interpretation and lead to false-positive results when used together with fluorochrome-labeled nuclear proteins detected with blue excitation and green emission. In order to avoid misinterpretations, extra precaution should be taken to prepare staining solutions with low DAPI concentration and DAPI (UV excitation) images should be acquired after all other higher wavelength images. Of various DNA dyes tested, Hoechst 33342 exhibited the lowest photoconversion while that for DAPI and Hoechst 33258 was much stronger. Different fixation methods did not substantially affect the strength of photoconversion. We also suggest avoiding the use of mounting medium with high glycerol concentrations since glycerol showed the strongest impact on photoconversion. This photoconversion effect cannot be avoided even when using narrow bandpass filter sets.

Post-translational N-glycosylation of type I transmembrane KCNE1 peptides: implications for membrane protein biogenesis and disease.

N-Glycosylation of membrane proteins is critical for their proper folding, co-assembly and subsequent matriculation through the secretory pathway. Here, we examine the kinetics of N-glycan addition to type I transmembrane KCNE1 K(+) channel ß-subunits, where point mutations that prevent N-glycosylation at one consensus site give rise to disorders of the cardiac rhythm and congenital deafness. We show that KCNE1 has two distinct N-glycosylation sites: a typical co-translational site and a consensus site ∼20 residues away that unexpectedly acquires N-glycans after protein synthesis (post-translational). Mutations that ablate the co-translational site concomitantly reduce glycosylation at the post-translational site, resulting in unglycosylated KCNE1 subunits that cannot reach the cell surface with their cognate K(+) channel. This long range inhibition is highly specific for post-translational N-glycosylation because mutagenic conversion of the KCNE1 post-translational site into a co-translational site restored both monoglycosylation and anterograde trafficking. These results directly explain how a single point mutation can prevent N-glycan attachment at multiple sites, providing a new biogenic mechanism for human disease.

KCNE1 subunits require co-assembly with K+ channels for efficient trafficking and cell surface expression.

KCNE peptides are a class of type I transmembrane beta subunits that assemble with and modulate the gating and ion conducting properties of a variety of voltage-gated K(+) channels. Accordingly, mutations that disrupt the assembly and trafficking of KCNE-K(+) channel complexes give rise to disease. The cellular mechanisms responsible for ensuring that KCNE peptides assemble with voltage-gated K(+) channels have yet to be elucidated. Using enzymatic deglycosylation, immunofluorescence, and quantitative cell surface labeling experiments, we show that KCNE1 peptides are retained in the early stages of the secretory pathway until they co-assemble with specific K(+) channel subunits; co-assembly mediates KCNE1 progression through the secretory pathway and results in cell surface expression. We also address an apparent discrepancy between our results and a previous study in human embryonic kidney cells, which showed wild type KCNE1 peptides can reach the plasma membrane without exogenously expressed K(+) channel subunits. By comparing KCNE1 trafficking in three cell lines, our data suggest that the errant KCNE1 trafficking observed in human embryonic kidney cells may be due, in part, to the presence of endogenous voltage-gated K(+) channels in these cells.