Crucial importance of PKC-β(I) in LFA-I-mediated locomotion of activated T cells

Crawling T cell locomotion in which activated lymphocyte function-associated antigen I (LFA-I) integrins participate is associated with translocation of the protein kinase C-β (PKC-β) isoenzyme to the microtubule cytoskeleton. In normal T cells and T lymphoma cell lines, this type of motility is accompanied by PKC-β-sensitive cytoskeletal rearrangements and the formation of trailing cell extensions, which are supported by microtubules. Expression of PKC-β(I) and enhanced green fluorescent protein (EGFP) in nonmotile PKC-β-deficient T cells restored their locomotory behavior in response to a triggering stimulus delivered via LFA-I and correlated directly with the degree of cell polarization. We have also shown that PKC-β(I) is a component of the tubulin-enriched LFA-I-cytoskeletal complex assembled upon LFA-I cross-linking. These observations may have physiological equivalents at advanced (post-integrin activation) stages of lymphocyte extravasation.