'Putting the squeeze' on the tight junction: understanding cytoskeletal regulation

The apical perijunctional actomyosin ring of epithelia is structurally asso ciated with the tight junction. The functional association between the tigh t junction and the perijunctional actomyosin ring was initially described i n studies using pharmacological agents that disrupt microfilaments. More re cently, this interaction has been studied in physiological, pathophysiologi cal, and molecular models of tight junction regulation. These studies have demonstrated the central role of actomyosin contraction in tight junction r egulation. With the identification of novel tight junction proteins and cha racterization of their protein:protein interactions comes the promise of de tailed understanding of the molecular interactions that mediate tight junct ion regulation.