Chromaffin cells of the adrenal medulla are innervated by the sympathetic nervous system. Stimulation causes chromaffin cells to fire action potentials, leading to the exocytosis of various classes of transmitters into the circulation. Low-frequency electrical stimulation (action potentials delivered at 0.5 Hz) causes adrenal chromaffin cells to selectively release catecholamines through a kiss...

Several bacterial pathogens hijack the actin assembly machinery and display intracellular motility in the cytosol of infected cells. At the cell cortex, intracellular motility leads to bacterial dissemination through formation of plasma membrane protrusions that resolve into vacuoles in adjacent cells. Here, we uncover a crucial role for actin network disassembly in dissemination of Listeria mo...

Localization of the actin crosslinking protein, alpha-actinin, to the cleavage furrow has been previously reported. However, its functions during cytokinesis remain poorly understood. We have analyzed the functions of alpha-actinin during cytokinesis by a combination of molecular manipulations and imaging-based techniques. alpha-actinin gradually dissipated from the cleavage furrow as cytokines...

Many lipid-tethered proteins and glycolipids exist as monomers and nanoclusters on the surface of living cells. The spatial distribution and dynamics of formation and breakup of nanoclusters does not reflect thermal and chemical equilibrium and is controlled by active remodeling of the underlying cortical actin. We propose a model for nanoclustering based on active hydrodynamics, wherein cell s...

Discussions of actin cell biology generally focus on the cortex, a thin, actin-rich layer of cytoplasm under the plasma membrane. Here we review the much less studied biology of actin filaments deeper in the cytoplasm and their recently revealed functions in mitosis and meiosis that are most prominent in large oocyte, egg and early embryo cells. The cellular functions of cytoplasmic actin range...

The first division of the Caenorhabditis elegans embryo is unequal, generating daughter cells with distinct fates. The differences between the cells are believed to result from the partitioning of cytoplasmic determinants during the first cell cycle. Actin microfilaments play a critical, but poorly defined, role in this event. In this paper, the actin cortex in live embryos is studied during cy...

Chromosome alignment on the spindle (top) is lost if Cdc42 is inactivated (bottom). N ar um iy a/ M ac m ill an Kyoto, Japan), and colleagues reveal microtubules at the cell cortex, are also needed for microtubule–kinetochore attachments, thus uniting two previously distant fields of study. Rho GTPases are needed during cytokinesis, when Rho helps build a contractile actin ring. Another Rho fam...

Type I myosins are highly conserved actin-based molecular motors that localize to the actin-rich cortex and participate in motility functions such as endocytosis, polarized morphogenesis, and cell migration. The COOH-terminal tail of yeast myosin-I proteins, Myo3p and Myo5p, contains an Src homology domain 3 (SH3) followed by an acidic domain. The myosin-I SH3 domain interacted with both Bee1p ...

New studies of moesin function during Drosophila oogenesis show that Dmoesin tethers actin to the oocyte membrane. Interestingly, Dmoesin and an intact cortex are also required to stabilise ooycte polarity.