No abstract

Summary The cell cortex serves as a critical nexus between the extracellular environment/cell membrane and the underlying cytoskeleton and cytoplasm. In many cells, the cell cortex is organized and maintained by the Ezrin, Radixin and Moesin (ERM) proteins, which have the ability to interact with both the plasma membrane and filamentous actin. Although this membrane-cytoskeletal linkage function is critical to stability of the cell cortex, recent studies indicate that this is only a part of what ERMs do in many cells. In addition to their role in binding filamentous actin, ERMs regulate signaling pathways through their ability to bind transmembrane receptors and link them to downstream signaling components. In this review we discuss recent evidence in a variety of cells indicating that ERMs serve as scaffolds to facilitate efficient signal transduction on the cytoplasmic face of the plasma membrane.

The regulation of cargo transport within neurons is not well understood. Neisch et al. use Drosophila genetics to identify a multiprotein STRIPAK complex required for autophagosome and dense core vesicle transport in neurons. PP2A activity within the complex is necessary for transport.

promote Slpr activation via accumulation at the cell cortex. Collectively, these results suggest that Rho1 promotes JNK pathway activity and therefore apoptosis through an interaction with Slpr, an upstream component of the JNK pathway.

Moesin, an ERM protein, negatively regulates RhoA by recruiting Conundrum/Rho GTPase–activating protein 18 to the apical cell cortex, thereby activating its RhoGAP function. Surprisingly, the data also show that activated Conundrum promotes cell proliferation, apparently through its ability to activate Rac1.