Insights Into The Role Of HSC70 In The Golgi Localization Of ARL5B

Abstract

ARL5B, an ARF-like small GTPase localized in the trans-Golgi regulates the transport between the Golgi and endosomes. Besides, ARL5B promotes migration and invasion in breast cancer cells. Although a few interacting partners are identified, the regulators of ARL5B are largely uncharacterized. Here, using GBP-pull down followed by mass spectrometry, we identified HSC70 (Heat shock cognate protein), as an interacting partner of ARL5B. Further, our pull-down and ITC based studies suggested that ARL5B is a substrate of HSC70. In addition, our in vitro studies suggested that the N-terminal of ARL5B is important for recognition by HSC70. Extending our studies in MDA-MB-231 cells, we observed that the depletion of HSC70 reduced the localization of ARL5B with Golgi markers. Finally, using in vitro reconstitution approach, we provide evidence that HSC70 facilitates the recruitment of ARL5B to the Golgi membrane. Collectively, our results suggest that the interaction of ARL5B with HSC70 is important for its Golgi localization and, consequently regulates intracellular trafficking in breast cancer cells.