Localization of specific epitopes on human microtubule-associated protein 2.
Microtubule-associated protein 2 (MAP-2) is an abundant neuronal cytoskeletal protein that binds to tubulin and stabilizes microtubules. Using fusion protein constructs we have defined the epitopes of 10 monoclonal antibodies (mAbs) to discrete regions of human MAP-2. Proteins were expressed in pATH vectors. After electrophoresis, immunoblotting was performed. By western blot analysis five of the mAbs (AP-14, AP-20, AP-21, AP-23, and AP-25) share epitopes with only the high molecular weight isoforms (MAP-2a, MAP-2b); two of the mAbs (AP-18 and tau 46) recognize MAP-2a, MAP-2b, and MAP-2c. Although AP-18 immunoreactivity was detected within heat-stable protein homogenates isolated from a human neuroblastoma cell line MSN, fusion protein constructs encompassing human MAP-2 were negative, suggesting that the AP-18 epitope is phosphorylated. Furthermore, AP-18 immunoreactivity was lost after alkaline phosphatase treatment of heat-stable protein preparations from MSN cells. Four of the mAbs (322, 636, 635, and 39) recognize epitopes located within amino acids 169-219 of human MAP-2. AP-21 maps to a region between amino acids 553 and 645. AP-23 maps between amino acids 645 and 993, whereas AP-20, AP-14, and AP-25 map between amino acids 995 and 1332. Expression of the region of MAP-2 between amino acids 1787 and 1824 was positive to tau 46.
Kalcheva
N
N
Department of Pathology, Albert Einstein College of Medicine, Bronx, New York 10461.
Albala
J S
JS
Binder
L I
LI
Shafit-Zagardo
B
B
D000469:Alkaline Phosphatase / Q000494:pharmacology; D000911:Antibodies, Monoclonal; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes / Q000032:analysis*; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D008970:Molecular Weight; D009447:Neuroblastoma; D010766:Phosphorylation; D011993:Recombinant Fusion Proteins / Q000276:immunology; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D000939:Epitopes; D008869:Microtubule-Associated Proteins; D011993:Recombinant Fusion Proteins; D000469:Alkaline Phosphatase