Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY 13210.
Mol Biol Cell. 2023 Jun 1;34(7):ar65. doi: 10.1091/mbc.E22-10-0455. Epub 2023 Apr 12.
Rab GTPase-mediated vesicle trafficking of cell surface proteins, including integrins, through endocytic and recycling pathways is important in controlling cell-extracellular matrix interactions during cell migration. The focal adhesion adaptor protein, paxillin, plays a central role in regulating adhesion dynamics and was previously shown to promote anterograde vesicle trafficking through modulation of microtubule acetylation via its inhibition of the deacetylase HDAC6. The role of paxillin in retrograde trafficking is unknown. Herein, we identified a role for paxillin in the modulation of the Rab5 GTPase, which is necessary for regulating early endosome dynamics and focal adhesion turnover. Using MDA-MB-231 breast cancer cells and paxillin (-/-) fibroblasts, paxillin was shown to impact Rab5-associated vesicle size and distribution, as well as Rab5 GTPase activity, through its modulation of HDAC6. Using a combination of real-time imaging and particle tracking analysis, paxillin was shown to promote Rab5-associated vesicle motility through inhibition of HDAC6-mediated micro-tubule deacetylation, along with the localization of active integrin to focal adhesions.
Rab GTPase 介导线粒体转运细胞表面蛋白（包括整合素）通过内吞和回收途径，在控制细胞迁移过程中的细胞-细胞外基质相互作用中起着重要作用。粘着斑衔接蛋白 paxillin 在调节黏附动力学中起着核心作用，先前的研究表明，它通过抑制去乙酰化酶 HDAC6 来调节微管乙酰化，从而促进正向囊泡运输。paxillin 在逆行运输中的作用尚不清楚。本文中，我们确定了 paxillin 在调节 Rab5 GTPase 中的作用，Rab5 GTPase 对于调节早期内体动力学和粘着斑周转率是必需的。使用 MDA-MB-231 乳腺癌细胞和 paxillin（-/-）成纤维细胞，通过其对 HDAC6 的调节，paxillin 显示出影响 Rab5 相关囊泡大小和分布以及 Rab5 GTPase 活性的作用。通过实时成像和颗粒跟踪分析的结合，paxillin 通过抑制 HDAC6 介导的微管去乙酰化，以及将活性整合素定位到粘着斑，从而促进 Rab5 相关囊泡的运动。
