Phosphorylation of the beta-subunit of CD11/CD18 integrins by protein kinase C correlates with leukocyte adhesion.
Adhesion of activated leukocytes to cells is of critical functional importance. The adhesion is known to be mediated mainly by the CD11/CD18 integrins, also known as leukocytic cell adhesion molecules, or Leu-CAM. We have now studied the phosphorylation of Leu-CAM by protein kinase C and the correlation of phosphorylation with the generation of the adhesive phenotype among human peripheral blood mononuclear leukocytes during cell activation. We here show that a good correlation exists between the phosphorylation of the beta subunit of Leu-CAM (CD18), and the extent of cell-to-cell adhesion. The phosphorylated CD18 subunit was associated with both CD11a and CD11b. Purified protein kinase C was able to phosphorylate the beta subunit of isolated Leu-CAM in vitro. The phosphorylation occurred mainly on serine residues.
Valmu
L
L
Department of Biochemistry, University of Helsinki, Finland.
Autero
M
M
Siljander
P
P
Patarroyo
M
M
Gahmberg
C G
CG
D015703:Antigens, CD / Q000378:metabolism*; D018821:CD18 Antigens; D000001:Calcimycin / Q000494:pharmacology; D002448:Cell Adhesion; D006801:Humans; D066298:In Vitro Techniques; D016023:Integrins / Q000378:metabolism*; D007962:Leukocytes / Q000166:cytology / Q000378:metabolism*; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism; D011493:Protein Kinase C / Q000502:physiology*
D015703:Antigens, CD; D018821:CD18 Antigens; D016023:Integrins; D010768:Phosphoserine; D015240:Phorbol 12,13-Dibutyrate; D000001:Calcimycin; D011493:Protein Kinase C