A NHERF binding site links the βPDGFR to the cytoskeleton and regulates cell spreading and migration
A NHERF binding site links the βPDGFR to the cytoskeleton and regulates cell spreading and migration
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DOI：
10.1242/jcs.01156
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发表时间：
2004-06-15
影响因子：
4
通讯作者：
Ramesh, V
中科院分区：
文献类型：
--
作者：
James, MF;Beauchamp, RL;Ramesh, V
Na+/H+交换调节因子NHERF是一种多功能的衔接蛋白，参与广泛的生理活动。NHERF通过其C-末端与膜肌动蛋白细胞骨架连接蛋白的merlin和ezrin/radixin/moesin（MERM）家族结合，并且能够通过其PDZ 1结构域与β PDGF受体（β PDGFR）相互作用。因此，NHERF可能通过与MERM蛋白的相互作用将β PDGFR连接到肌动蛋白细胞骨架。在目前的研究中，我们已经研究了是否取消与NHERF的β PDGFR的相互作用的结果在肌动蛋白细胞骨架重排。我们已经在PDGFR缺陷的小鼠胚胎成纤维细胞中稳定表达了野生型β PDGFR、不能与NHERF相互作用的突变型β PDGFR（L1106 A）以及激酶缺陷型突变型受体（K634 R）。我们的观察结果表明，表达β PDGFR（L1106 A）的细胞与野生型和K634 R细胞相比，其在纤连蛋白上的扩散和迁移能力受损。L1106 A突变体细胞还显示了粘着斑数量的增加，在细胞周围的凝聚的F-肌动蛋白环和减少总粘着斑激酶（FAK）酪氨酸磷酸化。此外，我们发现NHERF和MERM蛋白可以作为betaPDGFR和FAK之间的中间桥接蛋白。因此，β PDGFR与NHERF的相互作用可能提供了细胞膜和皮质肌动蛋白细胞骨架之间的重要联系，而不依赖于受体活性。
The Na+/H+ exchanger regulatory factor, NHERF, is a multifunctional adapter protein involved in a wide range of physiological activities. NHERF associates with merlin and the ezrin/radixin/moesin (MERM) family of membrane-actin cytoskeletal linker proteins through its C-terminus and is capable of interacting via its PDZ1 domain to the betaPDGF receptor (betaPDGFR). Thus, NHERF, potentially links the betaPDGFR to the actin cytoskeleton through its interaction with MERM proteins. In the present study, we have examined whether abolishing the interaction of betaPDGFR with NHERF results in actin cytoskeletal rearrangements. We have stably expressed a wild-type betaPDGFR, a mutant betaPDGFR (L1106A) that is incapable of interacting with NHERF, as well as a kinase defective mutant receptor (K634R), in PDGFR-deficient mouse embryonic fibroblasts. Our observations indicate that cells expressing betaPDGFR (L1106A) were impaired in their ability to spread and migrate on fibronectin compared with wild-type and K634R cells. L1106A mutant cells also revealed an increased number of focal adhesions, a condensed F-actin ring at the cell periphery and a decrease in total focal adhesion kinase (FAK) tyrosine phosphorylation. Further, we show that NHERF and MERM proteins could act as intermediary bridging proteins between betaPDGFR and FAK. Thus, the interaction of betaPDGFR with NHERF may provide an essential link between the cell membrane and the cortical actin cytoskeleton independent of receptor activity.