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Small GTP-binding proteins (G proteins) exist in eukaryotes from yeast to human and constitute a superfamily consisting of more than 100 members. This superfamily is structurally classified into at least five families: the Ras, Rho, Rab, Sar1/Arf, and Ran families. They regulate a wide variety of cell functions as biological timers (biotimers) that initiate(More)
The ERM proteins, ezrin, radixin, and moesin, are involved in the actin filament/plasma membrane interaction as cross-linkers. CD44 has been identified as one of the major membrane binding partners for ERM proteins. To examine the CD44/ERM protein interaction in vitro, we produced mouse ezrin, radixin, moesin, and the glutathione-S-transferase (GST)/CD44(More)
Tumor-promoting phorbol esters such as 12-O-tetradecanoylphorbol-13-acetate (TPA) directly activate in vitro Ca2+-activated, phospholipid-dependent protein kinase (protein kinase C), which normally requires unsaturated diacylglycerol. Kinetic analysis indicates that TPA can substitute for diacylglycerol and greatly increases the affinity of the enzyme for(More)
PSD-95 is a component of postsynaptic densities in central synapses. It contains three PDZ domains that localize N-methyl-D-aspartate receptor subunit 2 (NMDA2 receptor) and K+ channels to synapses. In mouse forebrain, PSD-95 bound to the cytoplasmic COOH-termini of neuroligins, which are neuronal cell adhesion molecules that interact with beta-neurexins(More)
Cdc42 is a small GTPase of the Rho family which regulates the formation of actin filaments to generate filopodia. Although there are several proteins such as PAK, ACK and WASP (Wiskott-Aldrich syndrome protein) that bind Cdc42 directly, none of these can account for the filopodium formation induced by Cdc42. Here we demonstrate that before it can induce(More)
The cytomatrix at the active zone (CAZ) has been implicated in defining the site of Ca2+-dependent exocytosis of neurotransmitter. We have identified here a novel CAZ protein of approximately 120 kD from rat brain and named it CAST (CAZ-associated structural protein). CAST had no transmembrane segment, but had four coiled-coil domains and a putative(More)
The RHO1 gene encodes a homologue of mammalian RhoA small G-protein in the yeast Saccharomyces cerevisiae. Rho1p is required for bud formation and is localized at a bud tip or a cytokinesis site. We have recently shown that Bni1p is a potential target of Rho1p. Bni1p shares the FH1 and FH2 domains with proteins involved in cytokinesis or establishment of(More)
The Rho small G protein family, consisting of the Rho, Rac, and Cdc42 subfamilies, regulates various cell functions, such as cell shape change, cell motility, and cytokinesis, through reorganization of the actin cytoskeleton. We show here that the Rac and Rho subfamilies furthermore regulate cell-cell adhesion. We prepared MDCK cell lines stably expressing(More)
Although cAMP is well known to regulate exocytosis in many secretory cells, its direct target in the exocytotic machinery is not known. Here we show that cAMP-GEFII, a cAMP sensor, binds to Rim (Rab3-interacting molecule, Rab3 being a small G protein) and to a new isoform, Rim2, both of which are putative regulators of fusion of vesicles to the plasma(More)
Rho1p is a yeast homolog of mammalian RhoA small GTP-binding protein. Rho1p is localized at the growth sites and required for bud formation. We have recently shown that Bni1p is a potential target of Rho1p and that Bni1p regulates reorganization of the actin cytoskeleton through interactions with profilin, an actin monomer-binding protein. Using the yeast(More)