Microtubule Associated Protein 1A (MAP1A)

These proteins have been divided into 2 main groups by molecular mass, high molecular weight MAPs, which include MAP1A, MAP1B, and MAP2, and another group of intermediate-sized proteins, which include the abundant tau MAPs. MAP1B, also named MAP5, is a component of long cross-bridges between microtubules and is a filamentous molecule with a small spherical segment at one end. Lien et al. (1994) completely cloned and sequenced the human MAP1B gene. By comparison of human MAP1B with sequence databases, they identified a MAP1B-related gene that is probably the human homolog of rat MAP1A. The human MAP1A gene is expressed at high levels in brain and spinal cord and at much lower levels in muscle.