TY - JOUR
T1 - Saccharomyces cerevisiae Bzz1p is implicated with type I myosins in actin patch polarization and is able to recruit actin-polymerizing machinery in vitro
AU - Soulard, Alexandre
AU - Lechler, Terry
AU - Spiridonov, Vladislav
AU - Shevchenko, Andrej
AU - Shevchenko, Anna
AU - Li, Rong
AU - Winsor, Barbara
PY - 2002/11/1
Y1 - 2002/11/1
N2 - In Saccharomyces cerevisiae, the WASP (Wiskott-Aldrich syndrome protein) homologue Las17p (also called Bee1p) is an important component of cortical actin patches. Las17p is part of a high-molecular-weight protein complex that regulates Arp2/3 complex-dependent actin polymerization at the cell cortex and that includes the type I myosins Myo3p and Myo5p and verprolin (Vrp1p). To identify other factors implicated with this complex in actin regulation, we isolated proteins that bind to Las17p by two-hybrid screening and affinity chromatography. Here, we report the characterization of Lsb7/Bzz1p (for Las seventeen binding protein 7), an Src homology 3 (SH3) domain protein that interacts directly with Las17p via a polyproline-SH3 interaction. Bzz1p coimmunoprecipitates in a complex with Las17p, Vrp1p, Myo3/5p, Bbc1p, Hsp70p, and actin. It colocalizes with cortical actin patches and with Las17p. This localization is dependent on Las17p, but not on F-actin. Bzz1p interacts physically and genetically with type I myosins. While deletion of BZZI shows no obvious phenotype, simultaneous deletion of the BZZ1, MY03, and MY05 genes is lethal. Overexpression of Bzz1p inhibits cell growth, and a bzz1ΔA myo5Δ double mutant is unable to restore actin polarity after NaCI stress. Finally, Bzz1p in vitro is able to recruit a functional actin polymerization machinery through its SH3 domains. Its interactions with Las17p, Vrp1p, and the type I myosins are essential for this process. This suggests that Bzz1p could be implicated in the regulation of actin polymerization.
AB - In Saccharomyces cerevisiae, the WASP (Wiskott-Aldrich syndrome protein) homologue Las17p (also called Bee1p) is an important component of cortical actin patches. Las17p is part of a high-molecular-weight protein complex that regulates Arp2/3 complex-dependent actin polymerization at the cell cortex and that includes the type I myosins Myo3p and Myo5p and verprolin (Vrp1p). To identify other factors implicated with this complex in actin regulation, we isolated proteins that bind to Las17p by two-hybrid screening and affinity chromatography. Here, we report the characterization of Lsb7/Bzz1p (for Las seventeen binding protein 7), an Src homology 3 (SH3) domain protein that interacts directly with Las17p via a polyproline-SH3 interaction. Bzz1p coimmunoprecipitates in a complex with Las17p, Vrp1p, Myo3/5p, Bbc1p, Hsp70p, and actin. It colocalizes with cortical actin patches and with Las17p. This localization is dependent on Las17p, but not on F-actin. Bzz1p interacts physically and genetically with type I myosins. While deletion of BZZI shows no obvious phenotype, simultaneous deletion of the BZZ1, MY03, and MY05 genes is lethal. Overexpression of Bzz1p inhibits cell growth, and a bzz1ΔA myo5Δ double mutant is unable to restore actin polarity after NaCI stress. Finally, Bzz1p in vitro is able to recruit a functional actin polymerization machinery through its SH3 domains. Its interactions with Las17p, Vrp1p, and the type I myosins are essential for this process. This suggests that Bzz1p could be implicated in the regulation of actin polymerization.
UR - http://www.scopus.com/inward/record.url?scp=0036840975&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0036840975&partnerID=8YFLogxK
U2 - 10.1128/MCB.22.22.7889-7906.2002
DO - 10.1128/MCB.22.22.7889-7906.2002
M3 - Article
C2 - 12391157
AN - SCOPUS:0036840975
VL - 22
SP - 7889
EP - 7906
JO - Molecular and Cellular Biology
JF - Molecular and Cellular Biology
SN - 0270-7306
IS - 22
ER -