Abstract

The long-term goal of this project is to understand the molecular mechanism by which proteins are transported across or are inserted into the mammalian endoplasmic reticulum (ER) membrane. We have established reconstituted proteoliposome and soluble systems with purified membrane protein components which reproduce the overall translocation process and partial reactions. The minimum translocation apparatus of the ER membrane comprises only the heterotrimeric Sec61p complex, the TRAM protein, and the SRP receptor. We now propose to perform a thorough analysis of the mechanism of translocation. Specifically, we will use questions: 1. How is cotranslational translocation initiated? 2. How do ribosomes interact with the Sec61p channel? 3. How are membrane proteins inserted into the lipid bilayer? 4. What is the function of the mammalian homologs of Sec62p and Sec63p? These studies will contribute significantly to our understanding of the first and decisive step in the biosynthesis of a large of class proteins, proteins of the plasma membrane, of lysosomes, and of all organelles of the secretory pathway.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM052586-08
Application #
6519651
Study Section
Molecular Cytology Study Section (CTY)
Program Officer
Shapiro, Bert I
Project Start
1995-05-01
Project End
2003-04-30
Budget Start
2002-05-01
Budget End
2003-04-30
Support Year
8
Fiscal Year
2002
Total Cost
$227,630
Indirect Cost

  Institution

Name
Harvard University
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
082359691
City
Boston
State
MA
Country
United States
Zip Code
02115

  Publications

Bodnar, Nicholas O; Kim, Kelly H; Ji, Zhejian et al. (2018) Structure of the Cdc48 ATPase with its ubiquitin-binding cofactor Ufd1-Npl4. Nat Struct Mol Biol 25:616-622
Wu, Xudong; Rapoport, Tom A (2018) Mechanistic insights into ER-associated protein degradation. Curr Opin Cell Biol 53:22-28
Chen, Yu; Bensing, Barbara A; Seepersaud, Ravin et al. (2018) Unraveling the sequence of cytosolic reactions in the export of GspB adhesin from Streptococcus gordonii. J Biol Chem 293:5360-5373
Schoebel, Stefan; Mi, Wei; Stein, Alexander et al. (2017) Cryo-EM structure of the protein-conducting ERAD channel Hrd1 in complex with Hrd3. Nature 548:352-355
Bodnar, Nicholas O; Rapoport, Tom A (2017) Molecular Mechanism of Substrate Processing by the Cdc48 ATPase Complex. Cell 169:722-735.e9
Rapoport, Tom A; Li, Long; Park, Eunyong (2017) Structural and Mechanistic Insights into Protein Translocation. Annu Rev Cell Dev Biol 33:369-390
Tripathi, Arati; Mandon, Elisabet C; Gilmore, Reid et al. (2017) Two alternative binding mechanisms connect the protein translocation Sec71-Sec72 complex with heat shock proteins. J Biol Chem 292:8007-8018
Baldridge, Ryan D; Rapoport, Tom A (2016) Autoubiquitination of the Hrd1 Ligase Triggers Protein Retrotranslocation in ERAD. Cell 166:394-407
Li, Long; Park, Eunyong; Ling, JingJing et al. (2016) Crystal structure of a substrate-engaged SecY protein-translocation channel. Nature 531:395-399
Tan, Dongyan; Blok, Neil B; Rapoport, Tom A et al. (2016) Structures of the double-ring AAA ATPase Pex1-Pex6 involved in peroxisome biogenesis. FEBS J 283:986-92

Showing the most recent 10 out of 41 publications