title: Cdc42 and vesicle trafficking in polarized cells.
abstract: Cdc42, a highly conserved small GTPase of the Rho family, acts as a molecular switch to modulate a wide range of signaling pathways. Vesicle trafficking and cell polarity are two processes Cdc42 is known to regulate. Although the trafficking and polarity machineries are each well understood, how they interact to cross-regulate each other in cell polarization is still a mystery. Cdc42 is an interesting candidate that may integrate these two networks within the cell. Here we review findings on the interplay between Cdc42 and trafficking in yeast, Caenorhabditis elegans, Drosophila and mammalian cell culture systems, and discuss recent advances in our understanding of the function of Cdc42 and two of its effectors, the WASp-Arp2/3 and Par complexes, in regulating polarized traffic. Work in yeast suggests that the polarized distribution of Cdc42, which acts here as a key polarity determinant, requires input from multiple processes including endocytosis and recycling. In metazoan cells, Cdc42 can regulate several steps in the biosynthetic as well as endocytotic and recycling pathways. The recent discovery that the Par polarity complex co-operates with Cdc42 in the regulation of endocytosis and recycling opens exciting possibilities for the integration of polarity protein function and endocytotic machinery.
authors.affiliation: Department of Cell and Systems Biology, University of Toronto, 25 Harbord street, Toronto, Ontario, M5S 3G5, Canada. kathryn.harris@utoronto.ca
authors.forename: Kathryn P
authors.initials: KP
authors.lastname: Harris
authors.forename: Ulrich
authors.initials: U
authors.lastname: Tepass
mesh_terms: D051376:Actin-Related Protein 2-3 Complex / Q000378:metabolism; D000199:Actins / Q000378:metabolism; D000818:Animals; D017173:Caenorhabditis elegans / Q000196:embryology / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000378:metabolism*; D016764:Cell Polarity; D002478:Cells, Cultured; D004330:Drosophila / Q000196:embryology / Q000378:metabolism; D029721:Drosophila Proteins / Q000378:metabolism*; D004705:Endocytosis; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases; D012441:Saccharomyces cerevisiae / Q000254:growth & development / Q000378:metabolism; D022142:Secretory Vesicles / Q000378:metabolism*
chemical_list: D051376:Actin-Related Protein 2-3 Complex; D000199:Actins; D029742:Caenorhabditis elegans Proteins; C090145:Cdc42 protein, Drosophila; D018797:Cell Cycle Proteins; D029721:Drosophila Proteins; D047908:Intracellular Signaling Peptides and Proteins; C400774:baz protein, Drosophila; C081779:cdc-42 protein, C elegans; C097238:PAR-3 protein, C elegans; D017346:Protein Serine-Threonine Kinases; D019204:GTP-Binding Proteins