A Key Regulator of Cell Adhesion: Identification and Characterization of ImportantN-Glycosylation Sites on Integrin α5 for Cell Migration.
TheN-glycosylation of integrin α5β1 is thought to control many fundamental aspects of cell behavior, including cell adhesion and migration. However, the mechanism of howN-glycans function remains largely obscure. Here, we used a loss-of-function approach. Wild-type (WT) integrin α5 andN-glycosylation mutant S3-5 (sites 3 to 5) integrin α5, which contains fewerN-glycans, were stably reconstituted in α5 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 α5β1 was inhibited in S3-5 cells, which is a process that is related to the enhanced expression of active integrin α5β1 on the cell surface. Importantly, restoration ofN-glycosylation on the β-propeller domain of α5 reinstated the cell migration ability, active α5β1 expression, and internalization. Moreover, theseN-glycans are critical for α5-syndecan-4 complex formation. These findings indicate thatN-glycosylation on the β-propeller domain functions as a molecular switch to control the dynamics of α5β1 on the cell surface that in turn is required for optimum adhesion for cell migration.
Division of Regulatory Glycobiology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Miyagi, Japan.
Qinglei
Q
Hang
Division of Regulatory Glycobiology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Miyagi, Japan.
Tomoya
T
Isaji
Division of Regulatory Glycobiology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Miyagi, Japan.
Sicong
S
Hou
Division of Regulatory Glycobiology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Miyagi, Japan.|Department of Pharmacology, Pharmacy College, Nantong University, Nantong, Jiangsu, China.
Yuqin
Y
Wang
Division of Regulatory Glycobiology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Miyagi, Japan.
Tomohiko
T
Fukuda
Division of Regulatory Glycobiology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Miyagi, Japan jgu@tohoku-mpu.ac.jp.|Department of Pharmacology, Pharmacy College, Nantong University, Nantong, Jiangsu, China.
Jianguo
J
Gu
D002448:Cell Adhesion / Q000502:physiology*; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism*; D002465:Cell Movement / Q000502:physiology*; D051417:Focal Adhesion Kinase 1 / Q000378:metabolism; D006031:Glycosylation; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D039081:Integrin alpha5beta1 / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000378:metabolism; D010766:Phosphorylation; D017434:Protein Structure, Tertiary; D053671:Syndecan-4 / Q000378:metabolism
D039081:Integrin alpha5beta1; D046912:Multiprotein Complexes; C508304:SDC4 protein, human; D053671:Syndecan-4; D051417:Focal Adhesion Kinase 1; C496050:PTK2 protein, human
N-glycan; activation; complex formation; internalization