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.
Aguilar
Rubén C
RC
Department of Biology, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA.
Longhi
Silvia A
SA
Shaw
Jonathan D
JD
Yeh
Lan-Yu
LY
Kim
Sean
S
Schön
Arne
A
Freire
Ernesto
E
Hsu
Ariel
A
McCormick
William K
WK
Watson
Hadiya A
HA
Wendland
Beverly
B
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