Epsin N-terminal homology domains perform an essential function regulating Cdc42 through binding Cdc42 GTPase-activating proteins.
Epsins are endocytic proteins with a structured epsin N-terminal homology (ENTH) domain that binds phosphoinositides and a poorly structured C-terminal region that interacts with ubiquitin and endocytic machinery, including clathrin and endocytic scaffolding proteins. Yeast has two redundant genes encoding epsins, ENT1 and ENT2; deleting both genes is lethal. We demonstrate that the ENTH domain is both necessary and sufficient for viability of ent1Deltaent2Delta cells. Mutational analysis of the ENTH domain revealed a surface patch that is essential for viability and that binds guanine nucleotide triphosphatase-activating proteins for Cdc42, a critical regulator of cell polarity in all eukaryotes. Furthermore, the epsins contribute to regulation of specific Cdc42 signaling pathways in yeast cells. These data support a model in which the epsins function as spatial and temporal coordinators of endocytosis and cell polarity.
Department of Biology, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA.
Rubén C
RC
Aguilar
Silvia A
SA
Longhi
Jonathan D
JD
Shaw
Lan-Yu
LY
Yeh
Sean
S
Kim
Arne
A
Schön
Ernesto
E
Freire
Ariel
A
Hsu
William K
WK
McCormick
Hadiya A
HA
Watson
Beverly
B
Wendland
D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D033942:Adaptor Proteins, Vesicular Transport; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D016764:Cell Polarity; D004705:Endocytosis; D005800:Genes, Fungal; D008958:Models, Molecular; D009154:Mutation; D010641:Phenotype; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D033921:Vesicular Transport Proteins; D020846:cdc42 GTP-Binding Protein, Saccharomyces cerevisiae / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D002352:Carrier Proteins; C121319:ENT1 protein, S cerevisiae; C121321:ENT2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins; D020846:cdc42 GTP-Binding Protein, Saccharomyces cerevisiae