The exact function of MAP2 is unknown but MAPs may stabilize the microtubules against depolymerization. They also seem to have a stiffening effect on microtubules. Interacts with KNDC1 (via KIND2); the interaction enhances MAP2 phosphorylation and localizes KNDC1 to dendrites. Interacts with DPYSL5 (By similarity). Additional isoforms seem to exist. Isoform 3/MAP2c is expressed during embryonic brain development and until postanatal day 10. Isoform 2 is expressed throughout brain development. Phosphorylated at serine residues in K-X-G-S motifs by MAP/microtubule affinity-regulating kinase (MARK1 or MARK2), causing detachment from microtubules, and their disassembly. Isoform 3/MAP2c is probably phosphorylated by PKA at Ser-319, Ser-350 and Ser-382 and by FYN at Tyr-67. The interaction with KNDC1 enhances MAP2 threonine phosphorylation (By similarity).