RESEARCH
Understanding the Hsp70 chaperone code
Hsp70 is a universally conserved molecular chaperone that performs a wide variety of functions in the cell including folding of both newly synthesized and denatured protein “clients”. Although transcriptional regulation of Hsp70 has been highly studied, little is known about post-translational modifications on Hsp70 (known as the “Chaperone Code”) and their effects on in vivo function. We are studying the conditions that alter the PTMs on Hsp70 in yeast and human cells and the effect they have on in vivo function. For more information please see our latest review on Hsp70 PTMs here
Characterizing the "Client Code"
Over 20 years ago, the PI uncovered the first PTM-driven interaction of a chaperone, between Hsp90 and the Mpk1 MAP kinase. Our recent study published in PLOS Biology suggests that many Hsp70 interactions may also be driven by PTMs on clients (see here). We now believe that just as there is a Chaperone Code, there is a corresponding "Client Code". For our recent review on the Client Code, please see here.
The impact of the Hsp70 chaperone code on neurodegenerative disease
Many of the proteins involved in neurodegenerative disease are clients of Hsp70. This includes TDP-43, important in Amyotrophic Lateral Sclerosis (ALS). We are currently characterizing the TDP43-chaperone complex and are working to understand which Hsp70 PTMs are important for this interaction.
Understanding the role of DNAJA1 in cancer
Our previous studies uncovered a role for Hsp70, Hsp90 and DNAJA1 in the stability of Ribonucleotide reductase (RNR), an important enzyme required for repairing DNA (here). Following up from this, we performed a chemogenomic screen to identify the role of DNAJA1 in anticancer drug resistance. A substantial number of drugs become far more potent upon loss of DNAJA1. We validate several of these using the DNAJA1 inhibitor 116-9e on both prostate cancer cell culture and spheroids models (see here). We are now hoping to study these synergistic combinations in mice models.
Why do cells express so many highly-related and seemingly-related chaperones? Our research suggests that while they have overlapping roles, there are clear functional differences between them. We are currently using mass spectrometry techniques to characterize the interactomes of these isoforms in different organisms.
Using Prime Editing to study chaperone function
In the Truman Lab we are currently using Prime editing to:
-
manipulate chaperone/co-chaperone function
-
epitope tag chaperones for proteomic studies
-
randomly mutate chaperones in combination with anticancer drug screens.