This gene encodes a protein that belongs to the
microtubule-associated protein family. The proteins of this family were originally isolated since they copurify with
tubulin in polymerization experiments: tubulin in cell extracts can be made to polymerize to produce
microtubules (MT) under the influence of heat and the addition of
GTP, and the MT can then be collected by centrifugation. When this is done a series of microtubule associated proteins are collected along with the MT and can be detected by
SDS-PAGE and other methods. Brain extracts are rich in several of these proteins, MAP2 being one of these. The single MAP2 gene produces four major transcripts producing four proteins, MAP2A, MAP2B, MAP2C and MAP2D. MAP2A and MAP2B are very high molecular weight proteins, with apparent molecular weight on SDS-PAGE about 250 kDa, while MAP2C and MAP2D are much lower molecular weight forms with apparent SDS-PAGE size about 70 kDa. All forms of MAP2 share a common core sequence which includes MT binding domains, 18 amino acid sequences which are found in other MT associated proteins such as
MAP Tau and
MAP1B. The MAP2 isoforms are thought to be involved in MT assembly, which is an essential step in
neuritogenesis. MAP2 serves to stabilize MT growth by crosslinking MT with
intermediate filaments and other MTs. MAP2 isoforms are neuron-specific
cytoskeletal proteins enriched in
dendrites and
perikarya, implicating a role in determining and stabilizing neuronal morphology during
neuron development. As a result,
antibodies to MAP2 are widely used to identify neuronal cells and trace dendritic processes in experimental contexts. == Interactions ==