Kaushik Shelly, Ravi Archna, Hameed Feroz M, Low Boon Chuan
Cell Signaling and Developmental Biology Laboratory, Department of Biological Sciences, National University of Singapore, Singapore; Mechanobiology Institute, National University of Singapore, Singapore.
Cytoskeleton (Hoboken). 2014 Dec;71(12):677-94. doi: 10.1002/cm.21201. Epub 2015 Jan 31.
Deleted in Liver Cancer-1 (DLC1) is a RhoGTPase-activating protein (GAP) and a tumor suppressor often downregulated in cancers. It is localized to the focal adhesions (FAs) and its absence leads to enhanced cell migration, invasion, and metastasis. Although DLC1 interacts with focal adhesion kinase (FAK), talin, and tensin, its role in focal adhesions dynamics remains unclear. We examined the effect of DLC1 in Human Foreskin Fibroblasts and determined its localization, dynamics and impact on paxillin by Fluorescence Recovery After Photobleaching at both nascent and mature focal adhesions. During early cell spreading, DLC1 is preferentially localized at the inner/mature adhesions whereas phosphorylated paxillin occupies the outer/nascent FAs. In addition, DLC1 downregulates paxillin turnover in a process, that does not require its GAP activity. Instead, it requires the presence of FAK. Acting in concert, both DLC1 and FAK could provide a unique spatio-temporal mechanism to regulate paxillin function in tissue homeostasis.
肝癌缺失基因-1（DLC1）是一种RhoGTP酶激活蛋白（GAP），也是一种在癌症中常常下调的肿瘤抑制因子。它定位于粘着斑（FAs），其缺失会导致细胞迁移、侵袭和转移增强。尽管DLC1与粘着斑激酶（FAK）、踝蛋白和张力蛋白相互作用，但其在粘着斑动态变化中的作用仍不清楚。我们通过光漂白后荧光恢复技术，研究了DLC1在人包皮成纤维细胞中的作用，并确定了其在新生和成熟粘着斑处的定位、动态变化以及对桩蛋白的影响。在细胞早期铺展过程中，DLC1优先定位于内部/成熟粘着斑，而磷酸化的桩蛋白占据外部/新生粘着斑。此外，DLC1在一个不需要其GAP活性的过程中下调桩蛋白的周转。相反，这需要FAK的存在。DLC1和FAK协同作用，可以提供一种独特的时空机制来调节桩蛋白在组织稳态中的功能。
