Microtubule-associated proteins (MAPs) regulate microtubule stability and play critical roles in neuronal development and in maintaining the balance between neuronal plasticity and rigidity. MAP-light chain 3 beta (MAP-LC3β) and MAP-light chain 3 alpha (MAP-LC3α), both of which are mammalian homologs of yeast Apg8, are subunits that can associate with either MAP-1A or MAP-1B. While MAP-LC3β is essential for autophagy and is associated with autophagosome membranes after processing, MAP LC3α is involved in the formation of autophagosomal vacuoles and is localized to the intracytoplasmic membrane. MAP LC3α is expressed as two alternatively spliced isoforms that are expressed in testis, brain, heart, liver and skeletal muscle, but are absent in thymus and peripheral blood leukocytes.