Protein phosphatase-1 binding to Scd5p is important for regulation of actin organization and endocytosis in yeast
Protein phosphatase-1 binding to Scd5p is important for regulation of actin organization and endocytosis in yeast
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DOI：
10.1074/jbc.m208471200
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发表时间：
2002-12-13
影响因子：
4.8
通讯作者：
Lemmon, SK
中科院分区：
文献类型：
--
作者：
Chang, JS;Henry, K;Lemmon, SK
SCD5是酵母中的一个必需基因，它编码一种对酵母细胞内吞和肌动蛋白组织至关重要的蛋白质。以前的双杂交筛选显示Scd5p与Glc7p相互作用，Glc7p是一种酵母丝氨酸/苏氨酸特异性蛋白磷酸酶-1(PP1)，参与各种细胞过程。在体内，PP1底物的特异性通过与不同的调节或靶向亚基的结合来调节，其中许多亚基具有共同的PP1结合位点((V/I)XT，在-1或-2位有一个基本残基)。Scd5p包含两个潜在的PP1结合基序：KVDF(氨基酸240-243)和KKVRF(氨基酸272-276)。缺失分析将PP1结合结构域映射到Scd5p的包含这些基序的区域。因此，我们研究了突变这两个潜在的PP1结合位点的后果。虽然KVDF的突变没有影响，但KKVRF的改变显著减少了Scd5p与Glc7p的相互作用，导致了温度敏感的生长。此外，该突变还导致了液体相和受体介导的内吞作用和肌动蛋白组织的缺陷。过表达GLC7抑制了KKVRF突变体对温度敏感的生长，并部分挽救了肌动蛋白组织表型。这些结果为Scd5p是调控肌动蛋白组织和内吞作用的PP1亚基，或Scd5p是PP1底物，调节Scd5p在这些过程中的功能提供了证据。
SCD5, an essential gene, encodes a protein important for endocytosis and actin organization in yeast. Previous two-hybrid screens showed that Scd5p interacts with Glc7p, a yeast Ser/Thr-specific protein phosphatase-1 (PP1) that participates in a variety of cellular processes. PP1 substrate specificity in vivo is regulated by association with different regulatory or targeting subunits, many of which have a consensus PP1-binding site ((V/I)XT, with a basic residue at the -1 or -2 position). Scd5p contains two of these potential PP1-binding motifs: KVDF (amino acids 240-243) and KKVRF (amino acids 272-276). Deletion analysis mapped the PP1-binding domain to a region of Scd5p containing these motifs. Therefore, the consequence of mutating these two potential PP1-binding sites was examined. Although mutation of KVDF had no effect, alteration of KKVRF dramatically reduced Scd5p interaction with Glc7p and resulted in temperature-sensitive growth. Furthermore, this mutation caused defects in fluid phase and receptor-mediated endocytosis and actin organization. Overexpression of GLC7 suppressed the temperature-sensitive growth of the KKVRF mutant and partially rescued the actin organization phenotype. These results provide evidence that Scd5p is a PP1 targeting subunit for regulation of actin organization and endocytosis or that Scd5p is a PP1 substrate, which regulates the function of Scd5p in these processes.