A complete functional nicotinic acetylcholine receptor (AChR) consisted of five subunits of four different types arranged as alpha2, beta, gamma and delta. Each of the four subunits is coded by a separate and discrete mRNA. Thus, the synthesis of a complete functional AChR molecule involves complex processes including assembly of the four different types of subunits in a particular order. The mechanisms involved in a multi-subunit AChR assembly will be studied by expressing normal, and site directed mutant, AChR subunits from cloned cDNAs in various combinations in the large oocyte cells of the frog. Specific topics to be investigated include: (1) The requirement of post-translational modifications for assembly and membrane insertion. (2) The order in which different subunits are put together. (3) Identification and localization of incomplete AChR molecules in the surface membrane. (4) The intracellular compartments in which AChR assembly occurs. (5) The presence of signals on the AChR subunits required for assembly. This research should substantially improve our understanding of the mechanisms involved in the assembly and membrane insertion of the nicotinic AChR in particular and of multi-subunit membrane proteins in general.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS025928-02
Application #
3411477
Study Section
Neurological Sciences Subcommittee 1 (NLS)
Project Start
1988-12-01
Project End
1991-11-30
Budget Start
1989-12-01
Budget End
1990-11-30
Support Year
2
Fiscal Year
1990
Total Cost
Indirect Cost
Name
University of California Irvine
Department
Type
Schools of Arts and Sciences
DUNS #
161202122
City
Irvine
State
CA
Country
United States
Zip Code
92697
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Sumikawa, K; Nishizaki, T (1994) The amino acid residues 1-128 in the alpha subunit of the nicotinic acetylcholine receptor contain assembly signals. Brain Res Mol Brain Res 25:257-64
Goldin, A L; Sumikawa, K (1992) Preparation of RNA for injection into Xenopus oocytes. Methods Enzymol 207:279-97
Sumikawa, K (1992) Sequences on the N-terminus of ACh receptor subunits regulate their assembly. Brain Res Mol Brain Res 13:349-53
Sumikawa, K; Gehle, V M (1992) Assembly of mutant subunits of the nicotinic acetylcholine receptor lacking the conserved disulfide loop structure. J Biol Chem 267:6286-90
Okamoto, T; Sumikawa, K (1991) Antibiotics cause changes in the desensitization of ACh receptors expressed in Xenopus oocytes. Brain Res Mol Brain Res 9:165-8
Gehle, V M; Sumikawa, K (1991) Site-directed mutagenesis of the conserved N-glycosylation site on the nicotinic acetylcholine receptor subunits. Brain Res Mol Brain Res 11:17-25