Calmodulin-like protein enhances myosin-10 translation

Myosin-10 (Myo10) is involved in processes ranging from filopodial formation and extension to spindle orientation during cell division. Myo10 contains three IQ motifs that bind calmodulin and calmodulin-like protein (CLP) as light chains. We recently found that CLP expression up-regulates Myo10, leading to increased Myo10-dependent cell motility and filopodial extension [R.D. Bennett, et al., J. Biol. Chem. 282 (2007) 3205-3212]. CLP-dependent Myo10 up-regulation occurs without increase in Myo10 mRNA. We followed Myo10 degradation in vivo and in vitro and found that it was unaffected by CLP. Myo10 decayed rapidly with a half-life of approximately 2.5h. Using an in vitro transcription/translation system we determined that CLP increased Myo10 translation, resulting in a higher relative accumulation of Myo10 in the presence than in the absence of CLP. Our data suggest that CLP functions to increase translation of Myo10 possibly by acting as a chaperone for the emerging Myo10 heavy chain protein.