Enables kinesin binding activity and microtubule binding activity. Involved in microtubule polymerization and positive regulation of nematode male tail tip morphogenesis. Located in axon. Expressed in intestinal muscle; neurons; and tail. Used to study tauopathy. Human ortholog(s) of this gene implicated in Alzheimer's disease; brain disease (multiple); and breast cancer. Is an ortholog of human MAP4 (microtubule associated protein 4).