The formation of transport carriers (spherical vesicles and tubules) involves membrane budding, growth, and ultimately fission. We propose a mechanism of membrane budding, wherein the tilt and chirality of constituent molecules, confined to a patch of area A, induces buds of approximately 50-100 nm that are comparable to vesicles involved in endocytosis. Because such chiral and tilted lipid mol...

Cortical actin patches are the most prominent actin structure in budding and fission yeast. Patches assemble, move, and disassemble rapidly. We investigated the mechanisms underlying patch actin assembly and motility by studying actin filament ultrastructure within a patch. Actin patches were partially purified from Saccharomyces cerevisiae and examined by negative-stain electron microscopy (EM...

We show that Arf3p, a member of the ADP ribosylation family, is involved in the organization of actin cables and cortical patches in Saccharomyces cerevisiae. Profilin-deficient cells (pfy1Delta) have severe growth defects and lack actin cables. Overexpression of ARF3 restores actin cables and corrects growth defects in these cells. Cells deficient for the cortical patch proteins Las17p and Vrp...

Actin-filament disassembly is crucial for actin-based motility, to control filament network architecture and to regenerate subunits for assembly. Here, we examined the roles of three actin cytoskeletal proteins, coronin, cofilin and Aip1, which have been suggested to combine in various ways to control actin dynamics by promoting or regulating disassembly. We studied their functions during the e...

ALIX/AIP1 functions in enveloped virus budding, endosomal protein sorting, and many other cellular processes. Retroviruses, including HIV-1, SIV, and EIAV, bind and recruit ALIX through YPX(n)L late-domain motifs (X = any residue; n = 1-3). Crystal structures reveal that human ALIX is composed of an N-terminal Bro1 domain and a central domain that is composed of two extended three-helix bundles...

Severe acute respiratory syndrome coronavirus (SARS-CoV), an enveloped single-stranded positive-sense RNA virus, is a member of the genus Betacoronavirus , family Coronaviridae. The SARS-CoV envelope protein E small (?8.4 kDa) channel-forming membrane whose sequence highly conserved between and SARS-CoV-2. As viroporin, it involved in various aspects virus life cycle including assembly, budding...

Cytokinesis requires the polarization of the actin cytoskeleton, the secretion machinery, and the correct positioning of the division axis. Budding yeast cells commit to their cytokinesis plane by choosing a bud site and polarizing their growth. Iqg1p (Cyk1p) was previously implicated in cytokinesis (Epp and Chant, 1997; Lippincott and Li, 1998; Osman and Cerione, 1998), as well as in the estab...

this study was conducted to determine the chemical composition, degradability characteristics gas production as well as the phenomenon of the persian clover (trifolium resopinatum) when at some growth stages of the were early budding to full flowering, namely: early budding (i), full budding (ii), early flowering (iii) as well as full flowering stage (iv). four fistulated mehraban male sheep we...