ACTR1A: Proteins and Enzymes

The actin-related protein ACTR1A, a member of the superfamily of actin-related proteins, is the major subunit of the dynactin complex, a key component of the cytoplasmic dynein motor machinery. The major components of the dynactin complex, consisting of at least ten polypeptides, include ACTR1A. ACTR1A, the most abundant subunit in the dynactin complex, is most similar to conventional actin (>50% amino acid identity). The dynactin complex has been shown to localize to multiple structures within the cell, including membrane organelles, the centrosome, spindle poles, and spindle pole microtubules during mitosis and prometaphase kinetochores. It regulates dyneinmediated vesicle movement on microtubules as well as spindle assembly and cell division. ACTR1A overexpression in cells results in aberrant spindle morphologies and cell cycle delay at prometaphase, suggesting a possible function of ACTR1A/dynactin complex in progression through the prometaphase of mitosis.