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

Crawling T cell locomotion in which activated lymphocyte function-associate d antigen I (LFA-I) integrins participate is associated with translocation of the protein kinase C-beta (PKC-beta) isoenzyme to the microtubule cytosk eleton. In normal T cells and T lymphoma cell lines, this type of motility is accompanied by PKC-beta -sensitive cytoskeletal rearrangements and the f ormation of trailing cell extensions, which are supported by microtubules. Expression of PKC-beta (I) and enhanced green fluorescent protein (EGFP) in nonmotile PKC-beta -deficient T cells restored their locomotory behavior i n response to a triggering stimulus delivered via LFA-I and correlated dire ctly with the degree of cell polarization. We have also shown that PKC-beta (I) is a component of the tubulin-enriched LFA-I-cytoskeletal complex asse mbled upon LFA-I cross-linking. These observations may have physiological e quivalents at advanced (post-integrin activation) stages of lymphocyte extr avasation.