Microtubules, the primary component of the cytoskeletal network, interact with proteins called microtubule-associated proteins (MAPs).MAP9 is a microtubule-associated protein required for spindle function, mitotic progression, and cytokinesis.The microtubule-associated proteins can be divided into two groups, structural and dynamic. The MAP proteins function to stimulate tubulin assembly, enhance microtubule stability, influence the spatial distribution of microtubules within cells and utilize microtubule polarity to translocate cellular components. MAP-9 (microtubule-associated protein 9), also known as ASAP, is a 647 amino acid cytoplasmic protein that is constitutively expressed during the cell cycle. MAP-9 localizes to microtubules in interphase, associates with the mitotic spindle during mitosis and localizes to the central body during cytokinesis. Involved in organization of the bipolar mitotic spindle, MAP-9 is required for bipolar spindle assembly, mitosis progression and cytokinesis. MAP-9 may be involved in stabilizing interphase microtubules. Two isoforms of MAP-9 are produced due to alternative splicing events.