Structure and phosphorylation of microtubule-associated protein 2 (MAP 2).
Chymotryptic fragments of microtubule-associated protein 2 (MAP 2) containing the portion of the molecule responsible for promoting microtubule assembly were identified. These assembly-promoting fragments displaced intact MAP 2, but not MAP 1, from assembled microtubules. This indicates that the association of MAP 2 with the microtubule surface is reversible. Both the assembly-promoting fragments and fragments representing the portion of the MAP 2 molecule observed as a projection on the microtubule surface were found to contain sites for endogenous cyclic AMP-dependent phosphorylation. The projection fragments were capable of endogenous phosphorylation even after their physical separation from microtubules. This suggests an intimate association of a kinase activity with the projections. Detailed analysis of the properties of the chymotryptic fragments of MAP 2 has led to a map of the molecule showing the major sites of proteolytic attack and the sites of phosphorylation.
D000818:Animals; D002417:Cattle; D002918:Chymotrypsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D008869:Microtubule-Associated Proteins; D008870:Microtubules / Q000378:metabolism* / Q000648:ultrastructure; D009024:Morphogenesis; D010446:Peptide Fragments / Q000302:isolation & purification; D010766:Phosphorylation; D011485:Protein Binding; D011487:Protein Conformation; D011494:Protein Kinases / Q000378:metabolism; D011506:Proteins / Q000032:analysis* / Q000378:metabolism; D051381:Rats; D014357:Trypsin / Q000494:pharmacology; D014404:Tubulin / Q000378:metabolism
D008869:Microtubule-Associated Proteins; D010446:Peptide Fragments; D011506:Proteins; D014404:Tubulin; D000242:Cyclic AMP; D011494:Protein Kinases; D002918:Chymotrypsin; D014357:Trypsin