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Beta 3 integrin phosphorylation is essential for Arp3 organization into leukocyte alpha V beta 3-vitronectin adhesion contacts
- Source :
- Journal of cell science. 117(Pt 8)
- Publication Year :
- 2004
-
Abstract
- Integrins play a pivotal role in self-regulated hematopoietic adhesion and migration. Leukocyte alpha(V)beta(3) integrin-mediated adhesion to vitronectin requires protein kinase C activation and phosphorylation on tyrosine 747 of the beta(3) cytoplasmic tail. We have previously shown that beta(3) phosphorylation is required for Rho activation. In this study, an antibody specific to phosphorylated beta(3) tyrosine 747 was used to localize phosphorylated alpha(V)beta(3) in vitronectin adhesive structures. Early adhesion contacts containing phosphorylated beta(3) preceded actin stress fiber formation. beta(3) phosphorylation decreased progressively throughout the course of adhesion coincident with the appearance of actin stress fibers. Time-dependent increases in colocalization of beta(3) with tyrosine 402 phosphorylated Pyk2 in similar adhesive structures was observed, providing evidence for downstream signaling complex formation. Surprisingly, Arp3 organized into similar adhesion contacts in cells expressing wild-type beta(3) but not in those expressing a nonphosphorylatable mutant of beta(3), suggesting that beta(3) phosphorylation is required for sequestration of Arp3 to adhesion complexes. Suppression of actin stress fiber formation by an inhibitor to Rho kinase disrupted Arp3 organization while prolonging beta(3) phosphorylation throughout the adhesion time course. These data confirm a requirement for beta(3) phosphorylation in alpha(V)beta(3)-mediated adhesion to vitronectin and suggest that beta(3) phosphorylation permits signaling complex assembly at the adhesion site necessary for actin stress fiber formation in leukocytes.
- Subjects :
- Stress fiber
Integrin
macromolecular substances
Biology
Cell Adhesion
Leukocytes
Humans
Vitronectin
Phosphorylation
Cell adhesion
Beta (finance)
Fluorescent Antibody Technique, Indirect
Rho-associated protein kinase
Integrin beta3
Cell Biology
Adhesion
Integrin alphaVbeta3
Precipitin Tests
Cell biology
Cytoskeletal Proteins
Kinetics
Actin-Related Protein 3
Mutation
biology.protein
K562 Cells
Subjects
Details
- ISSN :
- 00219533
- Volume :
- 117
- Issue :
- Pt 8
- Database :
- OpenAIRE
- Journal :
- Journal of cell science
- Accession number :
- edsair.doi.dedup.....fce6b1180e39a4df5bf0507e7c59f32c