Regulation of the enzymatic and motor activities of myosin I

Myosins I were the first unconventional myosins to be purified and they rem ain the best characterized. They have been implicated in various motile pro cesses, including organelle translocation, ion channel gating and cytoskele tal reorganization but their exact cellular functions are still unclear. Al l members of the myosin I family, from yeast to man, have three structural domains: a catalytic head domain that binds ATP and actin; a tail domain be lieved to be involved in targeting the myosins to specific subcellular loca tions and a junction or neck domain that connects them and interacts with l ight chains. In this review we discuss how each of these three domains cont ributes to the regulation of myosin I enzymatic activity, motor activity an d subcellular localization. (C) 2000 Elsevier Science B.V. AU rights reserv ed.