Interaction of a receptor tyrosine kinase, EGF-R, with caveolins - Caveolin binding negatively regulates tyrosine and serine/threonine kinase activities
Interaction of a receptor tyrosine kinase, EGF-R, with caveolins - Caveolin binding negatively regulates tyrosine and serine/threonine kinase activities
复制标题
DOI：
10.1074/jbc.272.48.30429
复制
发表时间：
1997-11-28
影响因子：
4.8
通讯作者：
Lisanti, MP
中科院分区：
文献类型：
--
作者：
Couet, J;Sargiacomo, M;Lisanti, MP
Caveolin是一种分子量为21-24 kDa的膜蛋白，是细胞膜的主要成分。我们和其他人认为，小窝蛋白作为一种支架蛋白的功能，组织和集中在小窝膜内的小窝蛋白相互作用的信号分子。在这方面，已经表明小窝蛋白的胞质NH 2-末端结构域的20个氨基酸的膜近端区域足以介导小窝蛋白与信号蛋白，即G-蛋白、Src样激酶、eNOS和H-Ras的相互作用。这种小窝蛋白衍生的蛋白质结构域被称为小窝蛋白支架结构域。结合的小窝蛋白支架结构域功能抑制G蛋白α亚基，eNOS和Src样激酶的活性，这表明小窝蛋白结合也可能发挥负调节作用的信号transduction.Here，我们报告的直接相互作用的小窝蛋白与生长因子受体，EGF-R，一个已知的小窝相关受体酪氨酸激酶。先前已经使用噬菌体展示技术定义了两个共有小窝蛋白结合基序。这些基序之一存在于大多数已知受体酪氨酸激酶的保守激酶结构域（称为区域IX）内。我们现在发现，在EGF-R的激酶结构域中的这个caveolin结合基序可以介导EGF-R与caveolin 1和3的支架结构域的相互作用，但不与caveolin 2。此外，caveolin 1和3的支架结构域都在功能上抑制体外EGF-R激酶的自磷酸化。重要的是，这种小窝蛋白介导的EGF-R激酶的抑制可以通过添加EGF-R衍生肽来防止，所述EGF-R衍生肽（i）含有非常保守的小窝蛋白结合基序，并且（ii）位于EGF-R和大多数已知的受体酪氨酸激酶的激酶结构域内。类似的结果与蛋白激酶C，丝氨酸/苏氨酸激酶，表明小窝蛋白可能作为一个通用的激酶抑制剂，我们的研究结果的影响进行了讨论的背景下小窝介导的信号转导。在这方面，小窝耦合信号可能解释了线性信号通路如何广泛地分支和互连，形成信号模块或网络。
Caveolin, a 21-24-kDa integral membrane protein, is a principal component of caveolae membranes. We and others have suggested that caveolin functions as a scaffolding protein to organize and concentrate certain caveolin-interacting signaling molecules within caveolae membranes. In this regard, it has been shown that a 20-amino acid membrane-proximal region of the cytosolic NH2-terminal domain of caveolin is sufficient to mediate the interaction of caveolin with signaling proteins, namely G-proteins, Src-Like kinases, eNOS, and H-Ras. This caveolin-derived protein domain has been termed the caveolin scaffolding domain. Binding of the caveolin-scaffolding domain functionally suppresses the activity of G-protein alpha subunits, eNOS, and Src-Like kinases, suggesting that caveolin binding may also play a negative regulatory role in signal transduction.Here, we report the direct interaction of caveolin with a growth factor receptor, EGF-R, a known caveollae-associated receptor tyrosine kinase. Two consensus caveolin binding motifs have been previously defined using phage display technology. One of these motifs is present within the conserved kinase domains of most known receptor tyrosine kinases (termed region IX). We now show that this caveolin binding motif within the kinase domain of the EGF-R can mediate the interaction of the EGF-R with the scaffolding domains of caveolins 1 and 3 but not with caveolin 2, In addition, the scaffolding do mains of caveolins 1 and 3 both functionally inhibit the autophosphorylation of the EGF-R kinase in vitro. Importantly, this caveolin mediated inhibition of the EGF-R kinase could be prevented by the addition of an EGF-R-derived peptide that (i) contains a well conserved caveolin binding motif and (ii) is located within the kinase domain of the EGF-R and most known receptor tyrosine kinases. Similar results were obtained with protein kinase C, a serine/threonine kinase, suggesting that caveolin may function as a general kinase inhibitor, The implications of our results are discussed within the context of caveolae-mediated signal transduction. In this regard, caveolae-coupled signaling might explain how linear signaling pathways can branch and interconnect extensively, forming a signaling module or network.