Characterization of Pak2p, a pleckstrin homology domain-containing, p21-activated protein kinase from fission yeast
Characterization of Pak2p, a pleckstrin homology domain-containing, p21-activated protein kinase from fission yeast
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DOI：
10.1074/jbc.273.29.18490
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发表时间：
1998-07-17
影响因子：
4.8
通讯作者：
Chernoff, J
中科院分区：
文献类型：
--
作者：
Sells, MA;Barratt, JT;Chernoff, J
P21激活的蛋白激酶(PAK)与Rho家族GTP酶结合并被其激活，如CDC42和Rac。由于这些GTP酶在调节细胞极性、应激反应和细胞周期进程中起关键作用，PAK影响这些过程的能力已经被研究，我以前发现分裂酵母PAK1(+)编码一种重要的蛋白质，影响交配和细胞极性。在这里，我们鉴定了来自裂殖酵母的第二个pak基因(pak2(+))。与酿酒酵母蛋白Cla4p和Skm1p一样，裂解酵母pak2p除了含有PAK家族其他成员所共有的PAL结合域和蛋白激活域外，还含有一个N端的pleckstrin同源结构域。与PAK1(+)不同，Pak2+对P.pombe的营养生长或交配不是必需的。野生型pak2(+)等位基因的过表达抑制了与PAK1(+)缺失相关的致死性生长缺陷，这种抑制既需要Pak2p的pleckstrin同源结合域和PLL结合域，也需要激酶活性。Pak2p的很大一部分与膜成分有关，这种联系既由pleckstrin同源基因介导，也由PAL结合结构域介导。这些结果表明，S.pombe至少编码两个具有不同功能的pak基因，提示pak2p的膜定位是其生物学活性的关键，该定位受其与膜脂和cdc42p的相互作用的影响。
p21-activated kinases (PAKs) bind to and are activated by Rho family GTPases such as Cdc42 and Rac. Since these GTPases play key roles in regulating cell polarity, stress responses, and cell cycle progression, the ability of PAK to affect these processes has been examined, me previously showed that fission yeast pak1(+) encodes an essential protein that affects mating and cell polarity. Here, we characterize a second pak gene (pak2(+)) from Schizosaccharomyces pombe. Like the Saccharomyces cerevisiae proteins Cla4p and Skm1p, fission yeast Pak2p contains an N-terminal pleckstrin homology domain in addition to a pal-binding domain and a protein kinase domain that are common to other members of the PAK family. Unlike pak1(+), pak2+ is not essential for vegetative growth or for mating in S. pombe. Overexpression of the wild-type pak2(+) allele suppresses the lethal growth defect associated with deletion of pak1(+), and this suppression requires both the pleckstrin homology- and the pll-binding domains of Pak2p, as well as kinase activity. A substantial fraction of Pak2p is associated with membranous components, an association mediated both by the pleckstrin homology- and by the pal-binding domains. These results show that S. pombe encodes at least two pak genes with distinct functions and suggest that the membrane localization of Pak2p, directed by its interactions with membrane lipids and Cdc42p, is critical to its biological activity.