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An N-glycosylation site on the beta-propeller domain of the integrin alpha5 subunit plays key roles in both its function and site-specific modification by beta1,4-N-acetylglucosaminyltransferase III.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 2009 May 01; Vol. 284 (18), pp. 11873-81. Date of Electronic Publication: 2009 Mar 09. - Publication Year :
- 2009
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Abstract
- Recently we reported that N-glycans on the beta-propeller domain of the integrin alpha5 subunit (S-3,4,5) are essential for alpha5beta1 heterodimerization, expression, and cell adhesion. Herein to further investigate which N-glycosylation site is the most important for the biological function and regulation, we characterized the S-3,4,5 mutants in detail. We found that site-4 is a key site that can be specifically modified by N-acetylglucosaminyltransferase III (GnT-III). The introduction of bisecting GlcNAc into the S-3,4,5 mutant catalyzed by GnT-III decreased cell adhesion and migration on fibronectin, whereas overexpression of N-acetylglucosaminyltransferase V (GnT-V) promoted cell migration. The phenomenon is similar to previous observations that the functions of the wild-type alpha5 subunit were positively and negatively regulated by GnT-V and GnT-III, respectively, suggesting that the alpha5 subunit could be duplicated by the S-3,4,5 mutant. Interestingly GnT-III specifically modified the S-4,5 mutant but not the S-3,5 mutant. This result was confirmed by erythroagglutinating phytohemagglutinin lectin blot analysis. The reduction in cell adhesion was consistently observed in the S-4,5 mutant but not in the S-3,5 mutant cells. Furthermore mutation of site-4 alone resulted in a substantial decrease in erythroagglutinating phytohemagglutinin lectin staining and suppression of cell spread induced by GnT-III compared with that of either the site-3 single mutant or wild-type alpha5. These results, taken together, strongly suggest that N-glycosylation of site-4 on the alpha5 subunit is the most important site for its biological functions. To our knowledge, this is the first demonstration that site-specific modification of N-glycans by a glycosyltransferase results in functional regulation.
- Subjects :
- Animals
CHO Cells
Cell Adhesion physiology
Cricetinae
Cricetulus
Dimerization
Fibronectins
Glycosylation
HeLa Cells
Humans
Integrin alpha5 genetics
Integrin alpha5beta1 genetics
Integrin alpha5beta1 metabolism
Mutation
N-Acetylglucosaminyltransferases genetics
Cell Movement physiology
Integrin alpha5 metabolism
N-Acetylglucosaminyltransferases metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9258
- Volume :
- 284
- Issue :
- 18
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 19276077
- Full Text :
- https://doi.org/10.1074/jbc.M807660200