INHIBITION OF CELL-CYCLE PROGRESSION BY THE ALTERNATIVELY SPLICED INTEGRIN BETA(1C)

Integrins regulate cell growth, differentiation, and behavior in many systems. Integrin beta(1C) (beta(1S)) is an alternatively spliced vari ant of integrin beta(1) with a specific cytoplasmic domain and is expr essed in several human tissues. Human beta(1C) transiently expressed i n mouse 10T1/2 fibroblasts showed a diffuse pattern of cell surface st aining, whereas beta(1) localized to focal adhesions. Moderate concent rations of beta(1C) had no effect on actin stress fibers or focal adhe sions, but markedly inhibited DNA synthesis. Inhibition by beta(1C) ma pped to the late G(1) phase of the cell cycle, near the G(1)-S boundar y. Thus, alternative splicing of beta(1) results in transmission of di stinct signals that may regulate growth in vivo.