A single discrete Rab5-binding site in phosphoinositide 3-kinase ß is required for tumor cell invasion.

Phosphoinositide 3-kinase ß (PI3Kß) is regulated by receptor tyrosine kinases (RTKs), G protein-coupled receptors (GPCRs), and small GTPases such as Rac1 and Rab5. Our lab previously identified two residues (Gln596 and Ile597) in the helical domain of the catalytic subunit (p110ß) of PI3Kß whose mutation disrupts binding to Rab5. To better define the Rab5-p110ß interface, we performed alanine-scanning mutagenesis and analyzed Rab5 binding with an in vitro pulldown assay with GST-Rab5GTP Of the 35 p110ß helical domain mutants assayed, 11 disrupted binding to Rab5 without affecting Rac1 binding, basal lipid kinase activity, or Gßγ-stimulated kinase activity. These mutants defined the Rab5-binding interface within p110ß as consisting of two perpendicular α-helices in the helical domain that are adjacent to the initially identified Gln596 and Ile597 residues. Analysis of the Rab5-PI3Kß interaction by hydrogen-deuterium exchange MS identified p110ß peptides that overlap with these helices; no interactions were detected between Rab5 and other regions of p110ß or p85α. Similarly, the binding of Rab5 to isolated p85α could not be detected, and mutations in the Ras-binding domain (RBD) of p110ß had no effect on Rab5 binding. Whereas soluble Rab5 did not affect PI3Kß activity in vitro, the interaction of these two proteins was critical for chemotaxis, invasion, and gelatin degradation by breast cancer cells. Our results define a single, discrete Rab5-binding site in the p110ß helical domain, which may be useful for generating inhibitors to better define the physiological role of Rab5-PI3Kß coupling in vivo.

Prevalence of Asthma among Young Men Residing in Urban Areas with Different Sources of Air Pollution.

BACKGROUND: Asthma is a common respiratory disease, which is linked to air pollution. However, little is known about the effect of specific air pollution sources on asthma occurrence. OBJECTIVES: To assess individual asthma risk in three urban areas in Israel characterized by different primary sources of air pollution: predominantly traffic-related air pollution (Tel Aviv) or predominantly industrial air pollution (Haifa bay area and Hadera). METHODS: The medical records of 13,875, 16- 19-year-old males, who lived in the affected urban areas prior to their army recruitment and who underwent standard pre-military health examinations during 2012-2014, were examined. Nonparametric tests were applied to compare asthma prevalence, and binary logistic regressions were used to assess the asthma risk attributed to the residential locations of the subjects, controlling for confounders, such as socio-demographic status, body mass index, cognitive abilities, and education. RESULTS: The asthma rate among young males residing in Tel Aviv was 8.76%, compared to 6.96% in the Haifa bay area and 6.09% in Hadera. However, no statistically significant differences in asthma risk among the three urban areas was found in controlled logistic regressions (P > 0.20). This finding indicates that exposure to both industrial- and traffic-related air pollution is associated with asthma prevalence. CONCLUSIONS: Both industrial- and traffic-related air pollution have a negative effect on asthma risk in young males. Studies evaluating the association between asthma risk and specific air pollutants (e.g., sulfur dioxide, particulate matter, and nitrogen dioxide) are needed to ascertain the effects of individual air pollutants on asthma occurrence.

Different effects of long-term exposures to SO2 and NO2 air pollutants on asthma severity in young adults.

Numerous studies demonstrated that exposure to ambient air pollutants contributes to severity and frequency of asthma exacerbations. However, whether common air pollutants, such as nitrogen dioxide (NO2) and sulfur dioxide (SO2), exert differential effects on asthma occurrence and severity is unclear. The aim of this investigation was to determine whether exposure to NO2 and/or SO2 may initiate different long-term effects on prevalence and severity of asthma in young adults. Medical records of 137,040 males, 17 years old, who underwent standard premilitary service health examinations during 1999-2008 were examined. Air-pollution data for NO2 and SO2 were linked to the place of residence of each subject. The influence of specific air pollutants on asthma prevalence and severity was evaluated using bivariate logistic regression, controlling for individuals' sociodemographic attributes. For both ambient air pollutants, there was a significant dose-response effect on severity of asthma at ambient concentrations below the current National Ambient Air Quality Standards. However, in residential areas with high levels of SO2 (13.3-592.7µg/m(3)) and high levels of NO2 (27.2-43.2µg/m(3)) the risk of asthma occurrence was significantly higher than that in residential areas with high levels of NO2 (27.2-43.2 µg/m(3)) and intermediate levels (6.7-13.3 µg/m(3)) of SO2 pollution. The effects of exposure to SO2 and NO2 air pollutants on the respiratory airways system appear to differ, with possible implications regarding medical management, even in cases of exposure to mixtures of these pollutants.

Air Pollution and Respiratory Morbidity in Israel: A Review of Accumulated Empiric Evidence.

Studies of the respiratory effects of air pollution in Israel published in peer-reviewed journals have been infrequent. Most empiric evidence relates to the association between air pollution and childhood asthma; other air pollution effects on other illnesses are less thoroughly studied. Our evaluation provides a possible explanation for the quite contradictory results demonstrated in the various studies. Actual effect estimates appear to differ considerably, ranging from no air pollution effect to a reasonably strong association detected between PM10 and asthma. We attribute these discrepancies to different research methodologies and different types of data used in various studies.

Ribosome-associated vesicles: A dynamic subcompartment of the endoplasmic reticulum in secretory cells.

The endoplasmic reticulum (ER) is a highly dynamic network of membranes. Here, we combine live-cell microscopy with in situ cryo-electron tomography to directly visualize ER dynamics in several secretory cell types including pancreatic ß-cells and neurons under near-native conditions. Using these imaging approaches, we identify a novel, mobile form of ER, ribosome-associated vesicles (RAVs), found primarily in the cell periphery, which is conserved across different cell types and species. We show that RAVs exist as distinct, highly dynamic structures separate from the intact ER reticular architecture that interact with mitochondria via direct intermembrane contacts. These findings describe a new ER subcompartment within cells.

Lead Exposure in Military Outdoor Firing Ranges.

BACKGROUND: Several studies have reported significant airborne lead exposures during training at indoor firing ranges. Scarce attention has been given to airborne lead exposures in outdoor shooting ranges with automatic weapons. OBJECTIVE: To assess the prevalence and magnitude of airborne and blood lead levels (BLL) among firing instructors and shooters in military outdoor ranges. METHODS: Exposure assessment, for both trainees and instructors, included airborne and BLL during basic and advanced training at outdoor firing ranges. Personal airborne samples were collected in both day and night shooting during both training periods. RESULTS: During basic training, there is 95% likelihood that up to 25% of instructors and 99% likelihood that up to 5% of trainees might be exposed above the action level (AL) (25 µg/m(3)). During advanced training, there is 90% likelihood that 10% of instructors and 99% likelihood that up to 10% of trainees might be exposed above the AL. CONCLUSIONS: Military personnel participating in automatic weapon marksmanship training can be exposed to considerable levels of airborne lead during outdoor firing range training. As a result, the Israel Defense Force Medical Corp has classified firing range instructors as workers that require periodic medical examinations.