Protein export is fundamental to many cellular processes including secretion, organellar biogenesis, and signaling. Since hundreds to thousands of proteins must cross at least one membrane before arriving at their final destination, protein translocation is a basic process in cell biology. In prokaryotes and eukaryotes, most of the components required for efficient assembly and export of proteins into and across biological membranes are well known. In bacteria, the insertion of the majority of membrane proteins is catalyzed by a complex of proteins (SecYEG) that receives membrane protein precursors and ensures their proper distribution within the bilayer. However, there is a class of membrane proteins whose assembly occurs independently of the Sec complex. These Sec-independent membrane proteins were thought to assemble into membranes directly without the assistance of a protein complex. Recently, we discovered that the assembly of Sec-independent integral membrane proteins into the inner membrane of Escherichia coli is dependent on a new accessory protein coded by the yidC gene. YidC is a medium sized (60 kDa) integral membrane protein. Null mutations in YidC are lethal, indicating that YidC is essential for cell growth. Homologs of YidC have also been identified in mitochondria and chloroplasts. Depletion of YidC from growing cells inhibits membrane insertion of Sec-independent proteins. In addition, the assembly of Sec-dependent membrane proteins is significantly delayed, while there is no effect on the export of secreted proteins. In order to understand the role of YidC in membrane protein assembly we plan to pursue the following specific aims: (1) Examine the global role of YidC in membrane protein assembly; (2) Characterize the components involved in the YidC-dependent membrane assembly pathway; (3) Reconstitute YidC-dependent membrane assembly using purified components; and (4) Determine the sites of interaction between YidC and its substrates. These studies will help to understand this novel bacterial membrane protein assembly pathway and perhaps help to explain similar events in eukaryotic cells.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM063862-03
Application #
6636698
Study Section
Microbial Physiology and Genetics Subcommittee 2 (MBC)
Program Officer
Chin, Jean
Project Start
2001-06-01
Project End
2005-05-31
Budget Start
2003-06-01
Budget End
2004-05-31
Support Year
3
Fiscal Year
2003
Total Cost
$221,250
Indirect Cost
Name
Ohio State University
Department
Biochemistry
Type
Schools of Medicine
DUNS #
071650709
City
Columbus
State
OH
Country
United States
Zip Code
43210
Wang, Peng; Dalbey, Ross E (2011) Inserting membrane proteins: the YidC/Oxa1/Alb3 machinery in bacteria, mitochondria, and chloroplasts. Biochim Biophys Acta 1808:866-75
Stiegler, Natalie; Dalbey, Ross E; Kuhn, Andreas (2011) M13 procoat protein insertion into YidC and SecYEG proteoliposomes and liposomes. J Mol Biol 406:362-70
Dalbey, Ross E; Wang, Peng; Kuhn, Andreas (2011) Assembly of bacterial inner membrane proteins. Annu Rev Biochem 80:161-87
Belin, Dominique (2010) In vivo analysis of protein translocation to the Escherichia coli periplasm. Methods Mol Biol 619:103-16
Wang, Peng; Kuhn, Andreas; Dalbey, Ross E (2010) Global change of gene expression and cell physiology in YidC-depleted Escherichia coli. J Bacteriol 192:2193-209
Yuan, Jijun; Zweers, Jessica C; van Dijl, Jan Maarten et al. (2010) Protein transport across and into cell membranes in bacteria and archaea. Cell Mol Life Sci 67:179-99
Wang, Peng; Dalbey, Ross E (2010) In vitro and in vivo approaches to studying the bacterial signal peptide processing. Methods Mol Biol 619:21-37
Celebi, Nil; Dalbey, Ross E; Yuan, Jijun (2008) Mechanism and hydrophobic forces driving membrane protein insertion of subunit II of cytochrome bo 3 oxidase. J Mol Biol 375:1282-92
Klenner, Christian; Yuan, Jijun; Dalbey, Ross E et al. (2008) The Pf3 coat protein contacts TM1 and TM3 of YidC during membrane biogenesis. FEBS Lett 582:3967-72
Dong, Yuxia; Palmer, Sara R; Hasona, Adnan et al. (2008) Functional overlap but lack of complete cross-complementation of Streptococcus mutans and Escherichia coli YidC orthologs. J Bacteriol 190:2458-69

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