A Key Regulator of Cell Adhesion: Identification and Characterization of Important N-Glycosylation Sites on Integrin ?5 for Cell Migration.

ABSTRACT: The N-glycosylation of integrin ?5?1 is thought to control many fundamental aspects of cell behavior, including cell adhesion and migration. However, the mechanism of how N-glycans function remains largely obscure. Here, we used a loss-of-function approach. Wild-type (WT) integrin ?5 and N-glycosylation mutant S3-5 (sites 3 to 5) integrin ?5, which contains fewer N-glycans, were stably reconstituted in ?5 knockout cancer cells. We found that the migration ability of S3-5 cells was decreased in comparison with that of the WT. Interestingly, the levels of phosphorylated focal adhesion kinase and actin stress fiber formation were greatly enhanced in the S3-5 mutant. In a mechanistic manner, the internalization of active but not total integrin ?5?1 was inhibited in S3-5 cells, which is a process that is related to the enhanced expression of active integrin ?5?1 on the cell surface. Importantly, restoration of N-glycosylation on the ?-propeller domain of ?5 reinstated the cell migration ability, active ?5?1 expression, and internalization. Moreover, these N-glycans are critical for ?5-syndecan-4 complex formation. These findings indicate that N-glycosylation on the ?-propeller domain functions as a molecular switch to control the dynamics of ?5?1 on the cell surface that in turn is required for optimum adhesion for cell migration.

SUBMITTER: Hang Q 

PROVIDER: S-EPMC5394273 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature