Secreted and transmembrane proteins mediate intercellular communication, driving pathophysiological processes such as inflammation, tumor angiogenesis, and metastasis. Most secreted and many transmembrane proteins are difficult to target with small-molecule drugs, as they lack typical drug binding sites. One approach to this problem is to inhibit secreted and membrane proteins indirectly, by preventing their transport to the cell surface. In this grant application, we describe cotransin, a cyclodepsipeptide that inhibits protein secretion in a substrate-specific manner. We discovered that cotransin blocks one of the earliest steps in the life of a secreted protein: cotranslational translocation into the endoplasmic reticulum (ER), a process that requires a signal sequence at the N-terminus of a nascent polypeptide. By an unknown mechanism, cotransin interferes with the ability of the Sec61 translocation channel to open in response to a minority of signal sequences. The major goal of this project is to design and synthesize new chemical tools that will allow us to dissect the molecular basis of cotransin's biological activity. cotransin ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
1R01GM081644-01
Application #
7302272
Study Section
Synthetic and Biological Chemistry B Study Section (SBCB)
Program Officer
Fabian, Miles
Project Start
2007-09-10
Project End
2011-07-31
Budget Start
2007-09-10
Budget End
2008-07-31
Support Year
1
Fiscal Year
2007
Total Cost
$298,437
Indirect Cost
Name
University of California San Francisco
Department
Pharmacology
Type
Schools of Medicine
DUNS #
094878337
City
San Francisco
State
CA
Country
United States
Zip Code
94143
Mackinnon, Andrew L; Paavilainen, Ville O; Sharma, Ajay et al. (2014) An allosteric Sec61 inhibitor traps nascent transmembrane helices at the lateral gate. Elife 3:e01483
Paavilainen, Ville O; Taunton, Jack (2013) Proteostasis modulators with discriminating taste. Chem Biol 20:144-5
Lakkaraju, Asvin K K; Thankappan, Ratheeshkumar; Mary, Camille et al. (2012) Efficient secretion of small proteins in mammalian cells relies on Sec62-dependent posttranslational translocation. Mol Biol Cell 23:2712-22
Maifeld, Sarah V; MacKinnon, Andrew L; Garrison, Jennifer L et al. (2011) Secretory protein profiling reveals TNF-? inactivation by selective and promiscuous Sec61 modulators. Chem Biol 18:1082-8
Mackinnon, Andrew L; Taunton, Jack (2009) Target Identification by Diazirine Photo-Cross-linking and Click Chemistry. Curr Protoc Chem Biol 1:55-73
MacKinnon, Andrew L; Garrison, Jennifer L; Hegde, Ramanujan S et al. (2007) Photo-leucine incorporation reveals the target of a cyclodepsipeptide inhibitor of cotranslational translocation. J Am Chem Soc 129:14560-1