A two-tiered mechanism by which Cdc42 controls the localization and activation of an Arp2/3-activating motor complex in yeast

Citation
T. Lechler et al., A two-tiered mechanism by which Cdc42 controls the localization and activation of an Arp2/3-activating motor complex in yeast, J CELL BIOL, 155(2), 2001, pp. 261-270
Citations number
48
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Cell & Developmental Biology
Journal title
JOURNAL OF CELL BIOLOGY
ISSN journal
0021-9525 → ACNP
Volume
155
Issue
2
Year of publication
2001
Pages
261 - 270
Database
ISI
SICI code
0021-9525(20011015)155:2<261:ATMBWC>2.0.ZU;2-X
Abstract
The establishment of cell polarity in budding yeast involves assembly of ac tin filaments at specified cortical domains. Elucidation of the underlying mechanism requires an understanding of the machinery that controls actin po lymerization and how this machinery is in turn controlled by signaling prot eins that respond to polarity cues. We showed previously that the yeast ort hologue of the Wiskott-Aldrich Syndrome protein, Bee1/Las17p, and the type I myosins are key regulators of cortical actin polymerization. Here, we dem onstrate further that these proteins together with Vrp1p form a multivalent Arp2/3-activating complex. During cell polarization, a bifurcated signalin g pathway downstream of the Rho-type GTPase Cdc42p recruits and activates t his complex, leading to local assembly of actin filaments. One branch, whic h requires formin homologues, mediates the recruitment of the Bee1p complex to the cortical site where the activated Cdc42p resides. The other is medi ated by the p21-activated kinases, which activate the motor activity of myo sin-I through phosphorylation. Together, these findings provide insights in to the essential processes leading to polarization of the actin cytoskeleto n.