Sec4 is a small GTPase of the rab family that is associated with the secretory vesicles of yeast. Sec 4 interacts with different sets of proteins in its different nucleotide states. In its GDP bound state it interacts with GD1, a proteins that maintains Sec4 in the cytosol. In its nucleotide free state, Sec4 will interact with DSS4 or with Sec2. Dss4 acts to stimulate dissociation of nucleotides for Sec4, while Sec2, working in conjugation with the actin based cytoskeleton, is needed for the polarized concentration of secretory vesicles at sites of exocytosis. Fst1 is a proteins that interacts with Sec2 to negatively regulate its function. Several newly identified proteins will interact with Sec4 in its GTP bound state. A number of studies are proposed to address the mechanisms by which these proteins work together to control the cycle of Sec4 function and to allow it to fulfill its role in targeting vesicles to specialized regions of the cell surface. 1) We will define the structural domains of Sec2 that allow binding to Sec4, oligomerization, localization to the bud tip and interaction with Fst1. 2) We will determine the mechanism by which Sec2 is localized to the bud tip and identify factors that interact with its localization domain, possibly linking it to the cytoskeleton. 3) We will establish the role of Sec2 in Sec4 function, evaluating its effect on the GDP off rate, the GTP on rate and the interactions with Dss4, Gdi1 and the cytoskeleton. 4) We will analyze the role of two different suppressors of dominant negative alleles of SEC4;SMY1 and a novel gene encoding 27kD protein. 5) We will explore a novel approach to identify a GAP for Sec4 and pursue the function of several Sec4 interacting proteins and a highly conserved protein that interacts with Dss4.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Program Projects (P01)
Project #
3P01CA046128-13S2
Application #
6324631
Study Section
Project Start
2000-05-01
Project End
2000-12-31
Budget Start
1998-10-01
Budget End
1999-09-30
Support Year
13
Fiscal Year
2000
Total Cost
$254,111
Indirect Cost
Name
Yale University
Department
Type
DUNS #
082359691
City
New Haven
State
CT
Country
United States
Zip Code
06520
Saheki, Yasunori; Bian, Xin; Schauder, Curtis M et al. (2016) Control of plasma membrane lipid homeostasis by the extended synaptotagmins. Nat Cell Biol 18:504-15
Destaing, Olivier; Ferguson, Shawn M; Grichine, Alexei et al. (2013) Essential function of dynamin in the invasive properties and actin architecture of v-Src induced podosomes/invadosomes. PLoS One 8:e77956
Mao, Yuxin; Balkin, Daniel M; Zoncu, Roberto et al. (2009) A PH domain within OCRL bridges clathrin-mediated membrane trafficking to phosphoinositide metabolism. EMBO J 28:1831-42
Ferguson, Shawn M; Ferguson, Shawn; Raimondi, Andrea et al. (2009) Coordinated actions of actin and BAR proteins upstream of dynamin at endocytic clathrin-coated pits. Dev Cell 17:811-22
Chen, Hong; Ko, Genevieve; Zatti, Alessandra et al. (2009) Embryonic arrest at midgestation and disruption of Notch signaling produced by the absence of both epsin 1 and epsin 2 in mice. Proc Natl Acad Sci U S A 106:13838-43
Zoncu, Roberto; Perera, Rushika M; Balkin, Daniel M et al. (2009) A phosphoinositide switch controls the maturation and signaling properties of APPL endosomes. Cell 136:1110-21
Gong, Liang-Wei; De Camilli, Pietro (2008) Regulation of postsynaptic AMPA responses by synaptojanin 1. Proc Natl Acad Sci U S A 105:17561-6
Frost, Adam; Perera, Rushika; Roux, Aurelien et al. (2008) Structural basis of membrane invagination by F-BAR domains. Cell 132:807-17
Hayashi, Mitsuko; Raimondi, Andrea; O'Toole, Eileen et al. (2008) Cell- and stimulus-dependent heterogeneity of synaptic vesicle endocytic recycling mechanisms revealed by studies of dynamin 1-null neurons. Proc Natl Acad Sci U S A 105:2175-80
Destaing, Olivier; Sanjay, Archana; Itzstein, Cecile et al. (2008) The tyrosine kinase activity of c-Src regulates actin dynamics and organization of podosomes in osteoclasts. Mol Biol Cell 19:394-404

Showing the most recent 10 out of 167 publications