Phosphorylation and dephosphorylation in the proline-rich C-terminal domain of microtubule-associated protein 2.
The C-terminal domain of microtubule-associated protein 2 (MAP2) contains a proline-rich region and the tubulin-binding domain. We have generated antibodies to follow the phosphorylation state of the proline-rich domain. One of these antibodies (no. 305) has been raised against a synthetic peptide P (sequence RTPGTPGTPSY) phosphorylated at the threonine residues. This sequence is present in the proline-rich region of MAP2 and is phosphorylated in vitro by at least three different proline-directed protein kinases: p42mpk, p34cdc2, and GSK3 (glycogen-synthase kinase 3) alpha/beta. The MAP2 sites phosphorylated by these kinases are different, although all of them phosphorylate the C-terminal domain of MAP2 as determined by Staphylococcus aureus V8 protease mapping. Nonphosphorylated peptide P can be phosphorylated in vitro by all three kinases studied with similar efficiency. In high-molecular-mass MAP2, this sequence is highly phosphorylated in vivo at the late stages of rat development. This motif can be rapidly dephosphorylated in vitro by protein-phosphatase 1 (PP1) and 2A (PP2A) catalytic subunits but not by PP2B.
Sánchez
C
C
Centro de Biología Molecular Severo Ochoa, Facultad de Ciencias, Universidad Autónoma de Madrid, Spain.
Tompa
P
P
Szücs
K
K
Friedrich
P
P
Avila
J
J
D000818:Animals; D000906:Antibodies; D000918:Antibody Specificity; D001923:Brain Chemistry; D000939:Epitopes; D008869:Microtubule-Associated Proteins / Q000276:immunology / Q000378:metabolism*; D009842:Oligopeptides / Q000276:immunology / Q000378:metabolism*; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D010766:Phosphorylation; D011392:Proline; D038461:Proline-Directed Protein Kinases; D054645:Protein Phosphatase 1; D017346:Protein Serine-Threonine Kinases; D051381:Rats
D000906:Antibodies; D000939:Epitopes; D008869:Microtubule-Associated Proteins; D009842:Oligopeptides; D011392:Proline; D038461:Proline-Directed Protein Kinases; D017346:Protein Serine-Threonine Kinases; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1