The long-term goal of proposed research is to understand the biochemistry and cell biology of protein folding in eukaryotic cells. The proposed research will focus on folding events as they occur at the ribosome during synthesis of a polypeptide and will examine the role of molecular chaperones in the folding process. The conceptual framework required to understand the folding of proteins as they emerge from the ribosome originates from the principal investigator's previous work, which indicates that folding in the eukaryotic cytosol is mediated by a highly organized chaperone machinery that is coupled to translation. Dr. Frydman's working hypothesis is that the newly translated polypeptides are guided to their final conformation through a sequential and highly coupled chaperone pathway. Results from Dr. Frydman's laboratory also indicate that different subsets of cellular proteins exhibit different chaperone requirements. For the model proteins that are the focus of the proposed research, the folding pathway appears to involve two classes of chaperones, namely small chaperones, such as the Hsc70 proteins and the GIM/prefolclin complex, which act by stabilizing extended polypeptides, and the chaperonin TRiC, which by virtue of its ring-like structure creates an environment that is favorable for polypeptide folding. The objective of this proposal is to elucidate the mechanism by which chaperones mediate the folding of newly synthesized proteins in eukaryotic cells. The general strategy is to combine in vitro and in vivo approaches to obtain mechanistic and functional insights into the role of chaperones in cellular folding. Specifically the principal investigator will: 1) Define the chain-length dependence of the interactions of nascent polypeptides with chaperone proteins; 2) Assess the requirement of molecular chaperones in the folding of newly synthesized polypeptides; 3) Determine the mechanisms that mediate the recruitment of chaperone components to the ribosome-bound nascent chain; 4) Define the substrate spectrum of the cytosolic chaperones in intact cells.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM056433-09
Application #
6984773
Study Section
Biochemistry Study Section (BIO)
Program Officer
Wehrle, Janna P
Project Start
1997-09-01
Project End
2007-03-14
Budget Start
2005-12-01
Budget End
2007-03-14
Support Year
9
Fiscal Year
2006
Total Cost
$297,123
Indirect Cost
Name
Stanford University
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
009214214
City
Stanford
State
CA
Country
United States
Zip Code
94305
Sontag, Emily Mitchell; Samant, Rahul S; Frydman, Judith (2017) Mechanisms and Functions of Spatial Protein Quality Control. Annu Rev Biochem 86:97-122
Hanebuth, Marie A; Kityk, Roman; Fries, Sandra J et al. (2016) Multivalent contacts of the Hsp70 Ssb contribute to its architecture on ribosomes and nascent chain interaction. Nat Commun 7:13695
Chartron, Justin W; Hunt, Katherine C L; Frydman, Judith (2016) Cotranslational signal-independent SRP preloading during membrane targeting. Nature 536:224-8
Shen, Koning; Calamini, Barbara; Fauerbach, Jonathan A et al. (2016) Control of the structural landscape and neuronal proteotoxicity of mutant Huntingtin by domains flanking the polyQ tract. Elife 5:
Pechmann, Sebastian; Chartron, Justin W; Frydman, Judith (2014) Local slowdown of translation by nonoptimal codons promotes nascent-chain recognition by SRP in vivo. Nat Struct Mol Biol 21:1100-5
Pechmann, Sebastian; Frydman, Judith (2014) Interplay between chaperones and protein disorder promotes the evolution of protein networks. PLoS Comput Biol 10:e1003674
Sontag, Emily Mitchell; Vonk, Willianne I M; Frydman, Judith (2014) Sorting out the trash: the spatial nature of eukaryotic protein quality control. Curr Opin Cell Biol 26:139-146
Duttler, Stefanie; Pechmann, Sebastian; Frydman, Judith (2013) Principles of cotranslational ubiquitination and quality control at the ribosome. Mol Cell 50:379-93
Geller, Ron; Andino, Raul; Frydman, Judith (2013) Hsp90 inhibitors exhibit resistance-free antiviral activity against respiratory syncytial virus. PLoS One 8:e56762
Willmund, Felix; del Alamo, Marta; Pechmann, Sebastian et al. (2013) The cotranslational function of ribosome-associated Hsp70 in eukaryotic protein homeostasis. Cell 152:196-209

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