A Complex between FAK, RACK1, and PDE4D5 Controls Spreading Initiation and Cancer Cell Polarity
A Complex between FAK, RACK1, and PDE4D5 Controls Spreading Initiation and Cancer Cell Polarity
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DOI：
10.1016/j.cub.2010.04.042
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发表时间：
2010-06-22
期刊：
影响因子：
9.2
通讯作者：
Frame, Margaret C.
中科院分区：
文献类型：
--
作者：
Serrels, Bryan;Sandilands, Emma;Frame, Margaret C.
细胞生物学中的一个基本问题是细胞在感知到方向信号后如何通过极化来对环境做出反应。这需要蛋白质复合体在细胞中的不同定位，识别和了解这些复合体的功能是很重要的。在这里，我们描述了一种新的“方向感知”途径，它连接整合素效应分子粘着斑激酶(FAK[1-7])、分子支架蛋白RACK1[8-10]及其客户蛋白之一PDE4D5的活性，PDE4D5是一种降解cAMP的磷酸二酯酶。这种复合体被招募到新生的粘连中，并促进细胞的极性。我们鉴定了FAK FERM结构域残基，其突变会损害RACK1的结合。当内源性FAK在Cre-lox介导的重组缺失的癌细胞中重新表达时，RACK1结合受损的FAK突变蛋白不支持随着细胞扩散而形成新生的肌动蛋白黏附结构。这些癌细胞和FAK缺陷细胞一样，不能进行方向性反应，包括创伤诱导极化或趋化侵入三维基质凝胶。我们发现RACK1是连接FAK和PDE4D5招募的分子桥梁。FAK/RACK1/PDE4D5是一种新型的“方向感知”复合体，作用于将cAMP第二信使系统的特定成分招募到新生的整合素粘连和极化细胞的前沿。
A fundamental question in cell biology concerns how cells respond to their environment by polarizing after sensing directional cues. This requires the differential localization of protein complexes in cells, and it is important to identify and understand how these complexes function. Here we describe a novel "direction-sensing" pathway that links the integrin effector focal adhesion kinase (FAK [1-7]), the molecular scaffold protein RACK1 [8-10], and activity of one of its client proteins, PDE4D5, a cAMP-degrading phosphodiesterase. The complex is recruited to nascent adhesions and promotes cell polarity. We identify FAK FERM domain residues whose mutation impairs RACK1 binding. When re-expressed in cancer cells in which endogenous fak is deleted by Cre-lox-mediated recombination, the RACK1-binding-impaired FAK mutant protein does not support formation of nascent actin adhesion structures as cells spread. These cancer cells, like FAK-deficient cells, cannot undergo directional responses, including wound-induced polarization or chemotactic invasion into three-dimensional matrix gels. We show that RACK1 serves as the molecular bridge linking FAK to the recruitment of PDE4D5. FAK/RACK1/PDE4D5 is a novel 'direction-sensing' complex that acts to recruit specific components of the cAMP second-messenger system to nascent integrin adhesions and to the leading edge of polarizing cells.