MAP1A and MAP1B are microtubule-associated proteins which mediate the physical interactions between microtubules and components of the cytoskeleton. MAP1A and MAP1B each consist of a heavy chain subunit and multiple light chain subunits. The protein encoded by MAP1LC3A?microtubule associated protein 1 light chain 3 alpha) is one of the light chain subunits and can associate with either MAP1A or MAP1B. Two transcript variants encoding different isoforms have been found for MAP1LC3A. The expression of variant 1 is suppressed in many tumor cell lines, suggesting that may be involved in carcinogenesis.