Cortical Mechanics and Meiosis II Completion in Mammalian Oocytes Are Mediated by Myosin-II and Ezrin-Radixin-Moesin (ERM) Proteins

Analysis of mouse oocyte mechanics shows that effective tension drops 6-fold from prophase I to metaphase II; the metaphase II egg has a 2.5-fold tension differential between the cortex over the spindle and the opposite cortex. Manipulation of actin, myosin-II, or ERMs alters tension levels and induces spindle abnormalities during meiosis II

Dynamic relocalization of NHERF1 mediates chemotactic migration of ovarian cancer cells toward lysophosphatidic acid stimulation

NHERF1/EBP50 (Na+/H+ exchanger regulating factor 1; Ezrin-binding phosphoprotein of 50 kDa) organizes stable protein complexes beneath the apical membrane of polar epithelial cells. By contrast, in cancer cells without any fixed polarity, NHERF1 often localizes in the cytoplasm. The regulation of cytoplasmic NHERF1 and its role in cancer progression remain unclear. In this study, we found that, upon lysophosphatidic acid (LPA) stimulation, cytoplasmic NHERF1 rapidly translocated to the plasma membrane, and subsequently to cortical protrusion structures, of ovarian cancer cells. This movement depended on direct binding of NHERF1 to C-terminally phosphorylated ERM proteins (cpERMs). Moreover, NHERF1 depletion downregulated cpERMs and further impaired cpERM-dependent remodeling of the cell cortex, suggesting reciprocal regulation between these proteins. The LPA-induced protein complex was highly enriched in migratory pseudopodia, whose formation was impaired by overexpression of NHERF1 truncation mutants. Consistent with this, NHERF1 depletion in various types of cancer cells abolished chemotactic cell migration toward a LPA gradient. Taken together, our findings suggest that the high dynamics of cytosolic NHERF1 provide cancer cells with a means of controlling chemotactic migration. This capacity is likely to be essential for ovarian cancer progression in tumor microenvironments containing LPA

Estimation of secondary measles transmission from a healthcare worker in a hospital setting.

Measles among healthcare workers (HCWs) is associated with a significant risk of nosocomial transmission to susceptible patients. When a measles case occurs in the healthcare setting, most guidelines recommend exhaustive measures. To evaluate the effects of measures against measles transmission in the healthcare setting precisely, it is essential to determine whether secondary transmission generally occurs. This study describes, for the first time, the actual secondary transmission rate for a measles-infected HCW in a ward with no special air ventilation capacity. The routine treatment of a number of immunocompromised patients occurs in this ward, and thus patients as well as HCWs have a thorough understanding and practice of standard and extended precautions. Our paired serum sample study revealed that none of the people in the ward exposed to the HCW at the catarrhal stage over a period of 4 days exhibited elevated levels of antibodies against measles. We suggest that strict adherence to standard and expanded precautions among patients and HCWs may be effective for preventing the transmission of a highly airborne disease, such as measles

Mitotic redistribution of the mitochondrial network by Miro and Cenp-F

Although chromosome partitioning during mitosis is well studied, the molecular mechanisms that allow proper segregation of cytoplasmic organelles in human cells are poorly understood. Here we show that mitochondria interact with growing microtubule tips and are transported towards the daughter cell periphery at the end of mitosis. This phenomenon is promoted by the direct and cell cycle-dependent interaction of the mitochondrial protein Miro and the cytoskeletal-associated protein Cenp-F. Cenp-F is recruited to mitochondria by Miro at the time of cytokinesis and associates with microtubule growing tips. Cells devoid of Cenp-F or Miro show decreased spreading of the mitochondrial network as well as cytokinesis-specific defects in mitochondrial transport towards the cell periphery. Thus, Miro and Cenp-F promote anterograde mitochondrial movement and proper mitochondrial distribution in daughter cells

Dynamic actin remodeling during epithelial–mesenchymal transition depends on increased moesin expression

LifeAct-GFP, a fluorescent reporter for actin filaments, is used to uncover the dynamics of actin cytoskeleton remodeling in real time during TGF-β–induced EMT. Efficient actin filament remodeling and complete transition to a mesenchymal phenotype depend on an increase in expression of the ERM protein moesin

The activation of ezrin–radixin–moesin proteins is regulated by netrin-1 through Src kinase and RhoA/Rho kinase activities and mediates netrin-1–induced axon outgrowth

The axon guidance cue netrin-1 and its receptor DCC regulate axon outgrowth. Netrin-1 induces the activation of ERM proteins and their association with DCC in cortical neurons, and the activity of ERM proteins is required for netrin-1–dependent axon outgrowth