Expression of MacMARCKS restores cell adhesion to ICAM-1-coated surface

To evaluate the role of MacMARCKS, a major substrate of protein kinase C, i n cell adhesion: we selected a macrophage cell line, Wehi 274.1.7. Although surface expression of beta 2-integrins can be detected on these cells, the y lack the phorbol ester- or chemokine-induced adhesion to ICAM-1-coated su rface, an event mediated by beta 2-integrins. Concomitantly, these cells la ck expression of both MacMARCKS and its homologue, MARCKS. When wild type M acMARCKS was expressed in these cells, the phorbol ester induced adhesion t o ICAM-1-coated surface increased approximately 5-fold compared to Vector t ransfected control cells. To further investigate the potential physiologica l role of MacMARCKS in this adhesion event: we also tested the effect of mo nocyte chemotactic protein-1,and a 3-fold increase in the adhesion to ICAM- 1-coated surface was observed with MacMARCKS-transfected cells. Therefore, these data suggest that MacMARCKS is an essential component in regulating c ell adhesion.