SH3 DOMAINS DIRECT CELLULAR-LOCALIZATION OF SIGNALING MOLECULES
SH3 DOMAINS DIRECT CELLULAR-LOCALIZATION OF SIGNALING MOLECULES
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DOI：
10.1016/0092-8674(93)90296-3
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发表时间：
1993-07-16
期刊：
影响因子：
64.5
通讯作者：
SCHLESSINGER, J
中科院分区：
文献类型：
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作者：
BARSAGI, D;ROTIN, D;SCHLESSINGER, J
在这项研究中，我们描述了磷脂酶C-γ（PLC-γ）和衔接蛋白GRB 2的SH 2和SH 3域的细胞分布后，他们显微注射到活的大鼠胚胎成纤维细胞。使用免疫荧光显微镜，我们表明，PLC-γ的SH 2和SH 3结构域组成的截短的蛋白质被定位到肌动蛋白细胞骨架。当仅显微注射PLC-γ的SH 3结构域时，观察到类似的定位模式。相反，仅由PLC-γ的SH 2结构域组成的截短蛋白表现出弥散的细胞质分布。显微注射的GRB 2蛋白主要定位于膜皱褶，因为GRB 2蛋白含有SH 2功能丧失点突变。因此，GRB 2定位于膜皱褶不需要与酪氨酸磷酸化部分相互作用。然而，GRB 2蛋白与SH 3功能丧失点突变表现出弥漫性胞质分布。这些结果表明，SH 3结构域负责将信号分子靶向特定的亚细胞位置。
In this study we describe the cellular distribution of the SH2 and SH3 domains of phospholipase C-gamma (PLC-gamma) and of the adaptor protein GRB2 following their microinjection into living rat embryo fibroblasts. Using immunofluorescence microscopy, we show that a truncated protein composed of the SH2 and SH3 domains of PLC-gamma was localized to the actin cytoskeleton. A similar localization pattern was observed when only the SH3 domain of PLC-gamma was microinjected. In contrast, a truncated protein composed of only the SH2 domains of PLC-gamma exhibited diffuse cytoplasmic distribution. Microinjected GRB2 protein was localized primarily to membrane ruffles, as was GRB2 protein containing SH2 loss-of-function point mutations. Hence, the localization of GRB2 to membrane ruffles does not require interaction with tyrosine-phosphorylated moieties. However, GRB2 proteins with SH3 loss-of-function point mutations exhibited diffuse cytoplasmic distribution. These results indicate that SH3 domains are responsible for the targeting of signaling molecules to specific subcellular locations.