Yeast Dynamin Vps1 and Amphiphysin Rvs167 Function Together During Endocytosis

Abstract

Dynamins are a conserved family of proteins involved in many membrane fusion and fission events. Previously, the dynamin-related protein Vps1 was shown to localize to endocytic sites, and yeast carrying deletions for genes encoding both the BAR domain protein Rvs167 and Vps1 had a more severe endocytic scission defect than either deletion alone. Vps1 and Rvs167 localize to endocytic sites at the onset of invagination and disassemble concomitant with inward vesicle movement. Endocytosis is a highly regulated eukaryotic process in which small regions of the plasma membrane invaginate into the cell and are pinched off, resulting in a vesicle that is then able to fuse with endosomes and enter the endolysosomal system. The process is required for remodelling the surface of cells to ensure the appropriate complement of receptors and transporters are exposed.In yeast, more than 50 different proteins are involved in endocytosis, and many of these proteins assemble and disassemble in a transient and highly choreographed way at endocytic sites on the plasma membrane (1,2) (reviewed in 3). Careful analysis of the behaviour of proteins at the sites has allowed models to be generated that indicate distinct endocytic stages. Early stages are associated with localization of clathrin and other endocytic patch coat proteins, while later stages involve the actindriven invagination of the membrane, followed by scission to form a vesicle.

Retromer and the dynamin Vps1 cooperate in the retrieval of transmembrane proteins from vacuoles

“…2). Vps1 has previously been implicated in endocytosis (Nannapaneni et al, 2010;Smaczynska-de Rooij et al, 2012), similar to the known role of dynamin (Cocucci et al, 2012). At present, we do not yet know how Vps1 is recruited to the retromer tubules.…”

Visualizing the functional architecture of the endocytic machinery

“…However, the exact molecular mechanism of vesicle scission is still not understood. Neither Rvs, nor the yeast homolog of dynamin Vps1, are essential for scission, but they may regulate its timing or location (Kishimoto et al, 2011; Kukulski et al, 2012; Smaczynska-de Rooij et al, 2012). Interestingly, the location of actin polymerization and Myo5 corresponds closely to the site of scission, therefore polymerization and motor activities could have a role in scission (Jonsdottir and Li, 2004).…”

Endocytic Accessory Factors and Regulation of Clathrin-Mediated Endocytosis

“…It seems unlikely that dynamin-mediated scission represents a universal mechanism of vesicle budding because vesicles can bud from other membrane surfaces in the cell in a dynamin-independent manner (Campelo and Malhotra 2012). Moreover, in yeast, the dynamin homolog Vps1 is required for efficient endocytosis but is dispensable for endocytic vesicle budding per se, whereas the actin cytoskeleton is not (Aghamohammadzadeh and Ayscough 2009;Smaczynska-de et al 2012). In mammalian cells the opposite is true and dynamin is essential for endocytosis, whereas the actin cytoskeleton is only essential in some cell types or under certain conditions (Aghamohammadzadeh and Ayscough 2009; Boulant et al 2011).…”