Regulatory Roles of HSP90-Rich Extracellular Vesicles

Abstract

HSP90 is an essential protein in protein folding, cancer progression and wound healing. Originally, most studies were focused on the intracellular molecular chaperone role of HSP90. However, more recent studies, including ours, have reported the secretion of HSP90 and novel functions for this protein in the extracellular space (ex-HSP90). Additionally, HSP90 has been found to be a major cargo contained in extracellular vesicles (EV) such as exosomes. HSP90 can directly bind to and promote functions of CD91/LRP1 and receptor tyrosine kinases such as EGF receptor. HSP90 also regulates the recycling of Rab proteins that control the secretion of exosomes. This chapter reviews current knowledge and the future potential of ex-HSP90 and EV-HSP90.