High impact information on MAP1B

• Furthermore, this function is regulated by phosphorylation of MAP1B by GSK-3beta [1].
• Recent findings suggest that glycogen synthase kinase 3beta (GSK-3beta) phosphorylation of MAP1B may act as a molecular switch to regulate microtubule stability during axonogenesis [1].
• These results suggest that a major role of MAP1B in growing axons and growth cones is to regulate microtubule and actin filament stability [1].
• Similarly, NGF fails to activate GSK3beta phosphorylation of MAP1B in PC12 cells that lack TrkA receptors but express p75NTR receptors (PC12 nnr) [2].
• We have recently shown that nerve growth factor (NGF) induces the phosphorylation of the microtubule-associated protein 1B (MAP1B) by activating the serine/threonine kinase glycogen synthase kinase 3beta (GSK3beta) in a spatio-temporal pattern in PC12 cells that correlates tightly with neurite growth [2].

Biological context of MAP1B

• This upregulation does not require protein synthesis, suggesting a direct effect of the homeodomain on MAP1B transcription [3].
• The promoter region of MAP1B was cut into several subdomains, and each subdomain was tested for its ability to bind Engrailed and EnHD and to associate with Engrailed-containing cerebellum nuclear extracts [3].

Anatomical context of MAP1B

• We show by Northern analysis that distinct mRNAs are recognized by the claustrin and 3'-MRC cDNAs, and by RT-PCR that mRNAs encoding these distinct MAP1B-related molecules are present in embryonic chick brain and cardiac and smooth muscle [4].
• It is thus proposed that MAP1B, a cytoskeleton protein involved in neuronal growth and regeneration, is under homeoprotein transcriptional regulation [3].

Associations of MAP1B with chemical compounds

• Claustrin, an antiadhesive neural keratan sulfate proteoglycan, is structurally related to MAP1B [5].

Other interactions of MAP1B

• Our data therefore provide new evidence that alternatively spliced variants of MAP1B are expressed in brain, and that at least one of these variants encodes the claustrin proteoglycan [4].

Analytical, diagnostic and therapeutic context of MAP1B

• To further determine the relationship between these two proteins, we used antibodies against MAP1B and KSPGs in immunoblotting and immunohistochemical studies [5].
• Our laboratory has previously characterized a keratan sulfate proteoglycan, named claustrin, and shown by molecular cloning that claustrin and the mouse MAP1B protein share high homology, with claustrin representing a 5'-truncated fragment of MAP1B [4].

References