Disruption of beta(2)-integrin-cytoskeleton coupling abolishes the signaling capacity of these integrins on granulocytes.
Integrin-dependent adhesion and dynamic modulations of the actin network are prerequisites for normal cell locomotion. To investigate whether the actin microfilamentous system does play a role in regulation of beta(2)-integrin-induced signalling, we pretreated granulocytes with staurosporine, a well-known protein kinase inhibitor that has also been shown to disrupt the cytoskeleton of intact cells. Pretreatment with staurosporine completely inhibited the beta(2)-integrin-induced Ca(2+) signal and also its ability to trigger actin polymerisation. This inhibition was not related to phosphorylation of the CD18-chain of the beta(2)-integrin, nor to inhibition of protein kinases. Instead, association of beta(2)-integrins with the cortical cytoskeleton, which was observed in untreated cells, was abolished after exposure to staurosporine, indicating that beta(2)-integrin signalling depends on integrin-cytoskeleton interaction. These results suggest not only that the actin network provides an adhesive link to the extracellular matrix and a driving force for the locomotory response, but also that it participates in regulation of beta(2)-integrin signalling during granulocyte locomotion.
Hellberg
C
C
Department of Laboratory Medicine, Lund University, U-MAS, Malmö, Sweden.
Ydrenius
L
L
Axelsson
L
L
Andersson
T
T
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000494:pharmacology*; D000199:Actins / Q000378:metabolism*; D018821:CD18 Antigens / Q000187:drug effects / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D002448:Cell Adhesion; D003599:Cytoskeleton / Q000187:drug effects / Q000502:physiology*; D003600:Cytosol / Q000378:metabolism; D006098:Granulocytes / Q000502:physiology; D018922:HL-60 Cells; D006801:Humans; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D019311:Staurosporine / Q000494:pharmacology*
D000199:Actins; D018821:CD18 Antigens; D009240:N-Formylmethionine Leucyl-Phenylalanine; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D019311:Staurosporine; D002118:Calcium