The objective of the proposed work is to define how cytosolic molecular chaperone proteins function in protein quality control to facilitate the folding and degradation of membrane proteins. The approach to taken to solve this problem is to study the biogenesis of normal and disease causing mutant forms of the cystic fibrosis transmembrane conductance regulator (CFTR). Our previous studies which utilized cultured cells and cell free systems defined roles for the cytosolic Hsc70 chaperone system in facilitating both the folding and degradation of nascent endoplasmic reticulum (ER) forms of CFTR. Data generated in the last funding period indicate that Hsc70 acts in complex that contains the ER localized Hsp40 Hdj-2 to promote CFTR folding/assembly. In addition, we found Hsc70 to interact with a new type of co-chaperone termed CHIP that contains an E3 ubiquitin ligase domain termed the U-box, to facilitate CFTR ubiquitination and degradation. These data demonstrate that cytosolic Hsc70 functions in both the folding and degradation of membrane proteins and provide evidence that co-chaperones help mediate the partitioning of nascent membrane proteins between folding and degradation pathways. We now seek additional funding to extend these studies and propose a series of experiments that are designed to further elucidate the pathways for CFTR folding and degradation. These studies will be carried out in 3 specific aims.
Aim 1. Investigate roles that cytosolic and lumenal ER chaperones systems play in CFTR folding.
Aim 2. Determination of the mechanism by which the Hsp70/CHIP complex controls the partitioning of nascent CFTR between folding and degradation pathways.
Aim 3. Identify the components that facilitate the delivery of ubiquitinated CFTR to the proteasome. Overall, these studies will provide a comprehensive view of how the cell mediates the folding and degradation of CFTR. The long term objective of these studies is to provide information that can identify targets for development of therapeutic to treat CF.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM056981-10
Application #
7003806
Study Section
Medical Biochemistry Study Section (MEDB)
Program Officer
Wehrle, Janna P
Project Start
1998-01-01
Project End
2006-12-31
Budget Start
2006-01-01
Budget End
2006-12-31
Support Year
10
Fiscal Year
2006
Total Cost
$286,026
Indirect Cost
Name
University of North Carolina Chapel Hill
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
608195277
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Sopha, Pattarawut; Ren, Hong Yu; Grove, Diane E et al. (2017) Endoplasmic reticulum stress-induced degradation of DNAJB12 stimulates BOK accumulation and primes cancer cells for apoptosis. J Biol Chem 292:11792-11803
Cheng, Zhaokang; Zhu, Qiang; Dee, Rachel et al. (2017) Focal Adhesion Kinase-mediated Phosphorylation of Beclin1 Protein Suppresses Cardiomyocyte Autophagy and Initiates Hypertrophic Growth. J Biol Chem 292:2065-2079
Gentzsch, Martina; Ren, Hong Y; Houck, Scott A et al. (2016) Restoration of R117H CFTR folding and function in human airway cells through combination treatment with VX-809 and VX-770. Am J Physiol Lung Cell Mol Physiol 311:L550-9
Veit, Gudio; Avramescu, Radu G; Chiang, Annette N et al. (2016) From CFTR biology toward combinatorial pharmacotherapy: expanded classification of cystic fibrosis mutations. Mol Biol Cell 27:424-33
Vermulst, Marc; Denney, Ashley S; Lang, Michael J et al. (2015) Transcription errors induce proteotoxic stress and shorten cellular lifespan. Nat Commun 6:8065
Cyr, Douglas M; Ramos, Carlos H (2015) Specification of Hsp70 function by Type I and Type II Hsp40. Subcell Biochem 78:91-102
Wolfe, Katie J; Ren, Hong Yu; Trepte, Philipp et al. (2014) Polyglutamine-rich suppressors of huntingtin toxicity act upstream of Hsp70 and Sti1 in spatial quality control of amyloid-like proteins. PLoS One 9:e95914
Houck, Scott A; Ren, Hong Yu; Madden, Victoria J et al. (2014) Quality control autophagy degrades soluble ERAD-resistant conformers of the misfolded membrane protein GnRHR. Mol Cell 54:166-179
Suzuki, Shingo; Shuto, Tsuyoshi; Sato, Takashi et al. (2014) Inhibition of post-translational N-glycosylation by HRD1 that controls the fate of ABCG5/8 transporter. Sci Rep 4:4258
Ren, Hong Yu; Grove, Diane E; De La Rosa, Oxana et al. (2013) VX-809 corrects folding defects in cystic fibrosis transmembrane conductance regulator protein through action on membrane-spanning domain 1. Mol Biol Cell 24:3016-24

Showing the most recent 10 out of 36 publications