Folding and Activation of Client Proteins by the Hsp90 Molecular Chaperone Machine
Molecular chaperones regulate the folding of cellular proteins from synthesis until they are properly folded or degraded. The majority of molecular chaperones assist the folding of proteins that are mostly unfolded. The abundant, essential molecular chaperone Hsp90 (heat shock protein, 90 kDa) is unique among chaperones because it preferentially interacts with and is required for the activity of proteins that are almost completely folded. The client proteins that require Hsp90 for function have little or no sequence or structural homology, and little is known about how Hsp90 promotes activation of a select group of diverse cellular client proteins. The goal of this project is to identify the sites of interaction between Hsp90 and two very different client proteins. A panel of mutant forms of Hsp90 will be used as tools to identify and describe critical features of Hsp90 required for interaction with a protein kinase and a transcription factor. Once mutations that disrupt the interaction with two distinct client proteins in vivo are identified, further research will determine whether the mutations disrupt the in vitro assembly of Hsp90-client protein complexes using cell lysates and purified components. Additional research will focus on establishing whether select Hsp90 mutations indirectly disrupt client protein interaction by preventing interaction of Hsp90 with regulatory co-chaperone proteins. This research project will lead to clarification of the contact sites between Hsp90 and client proteins and a greater understanding of how Hsp90 and co-chaperones cooperate to promote activation of a diverse group of client proteins. This project will have broad impacts on understanding how Hsp90 interacts with diverse client proteins. This project will enable one graduate student and two undergraduate students per year to conduct independent research projects. All students will have the opportunity to develop skills in organizing and presenting data during laboratory meetings, undergraduate research poster forums and/or additional scientific conferences. Additional graduate and undergraduate students outside of this lab will be exposed to this work through scientific exchanges and seminars among faculty members within the Microbiology, Molecular Biology and Biochemistry department, and the Center for Reproductive Biology, which is a joint program with Washington State University. Through the NIH-INBRE program and the UDOC program that is part of the multi-state WWAMI medical school program, additional undergraduate students and high school students from underrepresented and minority groups will also be exposed to research in the laboratory.