Cyclical regulation of the exocyst and cell polarity determinants for polarized cell growth

被引:28
作者
Zajac, A [1 ]
Sun, XL [1 ]
Zhang, J [1 ]
Guo, W [1 ]
机构
[1] Univ Penn, Dept Biol, Philadelphia, PA 19104 USA
关键词
D O I
10.1091/mbc.E04-10-0896
中图分类号
Q2 [细胞生物学];
学科分类号
071009 ; 090102 ;
摘要
Polarized exocytosis is important for morphogenesis and cell growth. The exocyst is a multiprotein complex implicated in tethering secretory vesicles at specific sites of the plasma membrane for exocytosis. In the budding yeast, the exocyst is localized to sites of bud emergence or the tips of small daughter cells, where it mediates secretion and cell surface expansion. To understand how exocytosis is spatially controlled, we systematically analyzed the localization of Sec15p, a member of the exocyst complex and downstream effector of the rab protein Sec4p, in various mutants. We found that the polarized localization of wSec15p relies on functional upstream membrane traffic, activated rab protein Sec4p, and its guanine exchange factor Sec2p. The initial targeting of both Sec4p and Sec15p to the bud tip depends on polarized actin cable. However, different recycling mechanisms for rab and Sec15p may account for the different kinetics of polarization for these two proteins. We also found that Sec3p and Sec15p, though both members of the exocyst complex, rely on distinctive targeting mechanisms for their localization. The assembly of the exocyst may integrate various cellular signals to ensure that exocytosis is tightly controlled. Key regulators of cell polarity such as Cdc42p are important for the recruitment of the exocyst to the budding site. Conversely, we found that the proper localization of these cell polarity regulators themselves also requires a functional exocytosis pathway. We further report that Bem1p, a protein essential for the recruitment of signaling molecules for the establishment of cell polarity, interacts with the exocyst complex. We propose that a cyclical regulatory network contributes to the establishment and maintenance of polarized cell growth in yeast.
引用
收藏
页码:1500 / 1512
页数:13
相关论文
共 48 条
[1]   Involvement of the late secretory pathway in actin regulation and mRNA transport in yeast [J].
Aronov, S ;
Gerst, JE .
JOURNAL OF BIOLOGICAL CHEMISTRY, 2004, 279 (35) :36962-36971
[2]   High rates of actin filament turnover in budding yeast and roles for actin in establishment and maintenance of cell polarity revealed using the actin inhibitor latrunculin-A [J].
Ayscough, KR ;
Stryker, J ;
Pokala, N ;
Sanders, M ;
Crews, P ;
Drubin, DG .
JOURNAL OF CELL BIOLOGY, 1997, 137 (02) :399-416
[3]   USE OF A SCREEN FOR SYNTHETIC LETHAL AND MULTICOPY SUPPRESSEE MUTANTS TO IDENTIFY 2 NEW GENES INVOLVED IN MORPHOGENESIS IN SACCHAROMYCES-CEREVISIAE [J].
BENDER, A ;
PRINGLE, JR .
MOLECULAR AND CELLULAR BIOLOGY, 1991, 11 (03) :1295-1305
[4]   Assembly of scaffold-mediated complexes containing Cdc42p, the exchange factor Cdc24p and the effector Cla4p required for cell cycle-regulated phosphorylation of Cdc24p [J].
Bose, I ;
Irazoqui, JE ;
Moskow, JJ ;
Bardes, ESG ;
Zyla, TR ;
Lew, DJ .
JOURNAL OF BIOLOGICAL CHEMISTRY, 2001, 276 (10) :7176-7186
[5]   SEC15 PROTEIN, AN ESSENTIAL COMPONENT OF THE EXOCYTOTIC APPARATUS, IS ASSOCIATED WITH THE PLASMA-MEMBRANE AND WITH A SOLUBLE 19.5S PARTICLE [J].
BOWSER, R ;
NOVICK, P .
JOURNAL OF CELL BIOLOGY, 1991, 112 (06) :1117-1131
[6]   SEC9 IS A SNAP-25-LIKE COMPONENT OF A YEAST SNARE COMPLEX THAT MAY BE THE EFFECTOR OF SEC4 FUNCTION IN EXOCYTOSIS [J].
BRENNWALD, P ;
KEARNS, B ;
CHAMPION, K ;
KERANEN, S ;
BANKAITIS, V ;
NOVICK, P .
CELL, 1994, 79 (02) :245-258
[7]   A positive feedback loop stabilizes the guanine-nucleotide exchange factor Cdc24 at sites of polarization [J].
Butty, AC ;
Perrinjaquet, N ;
Petit, A ;
Jaquenoud, M ;
Segall, JE ;
Hofmann, K ;
Zwahlen, C ;
Peter, M .
EMBO JOURNAL, 2002, 21 (07) :1565-1576
[8]   The role of Far1p in linking the heterotrimeric G protein to polarity establishment proteins during yeast mating [J].
Butty, AC ;
Pryciak, PM ;
Huang, LS ;
Herskowitz, I ;
Peter, M .
SCIENCE, 1998, 282 (5393) :1511-1516
[9]   A YEAST GENE (BEM1) NECESSARY FOR CELL POLARIZATION WHOSE PRODUCT CONTAINS 2 SH3 DOMAINS [J].
CHENEVERT, J ;
CORRADO, K ;
BENDER, A ;
PRINGLE, J ;
HERSKOWITZ, I .
NATURE, 1992, 356 (6364) :77-79
[10]  
Chu S, 2004, TOP CURR GENET, V10, P89