Characterization of PCP-2, a novel receptor protein tyrosine phosphatase of the MAM domain family.
DNA sequences encoding a novel member of the receptor protein tyrosine phosphatase (R-PTP) family, termed PCP-2, were identified in a human pancreatic adenocarcinoma cDNA library. Human PCP-2 cDNA predicts a protein of 1430 amino acids with a calculated Mr of 160 kDa. The predicted PCP-2 enzyme consists of a 740 amino acid extracellular region, a single transmembrane domain, and a 666 amino acid intracellular portion. The extracellular sequence contains a MAM (meprin/A5/PTPmu) domain, an immunoglobulin-like domain and four fibronectin type III-like repeats, suggesting that it is a member of the PTPkappa and PTPmu subfamily. The intracellular region contains two tandemly-repeated protein tyrosine phosphatase domains. Northern blot analyses revealed a single transcript of 5.5 kilobases, which is expressed at different levels in many human tissues except spleen and placenta. Upon transfection of PCP-2 cDNA into human embryonic kidney fibroblast 293 cells, a protein with an apparent Mr of 180 000 was detected by immunoblot analysis. This size was reduced to the predicted Mr upon treatment with endoglycosidase F, indicating that PCP-2 is glycosylated and, hence, expressed at the cell surface. A potential role of PCP-2 in cell-cell recognition and adhesion is supported by its co-localization with cell adhesion molecules, such as catenin and E-cadherin, at sites of cell-cell contact.
Wang
H
H
Department of Molecular Biology, Max-Planck-Institute für Biochemie, Germany.
Lian
Z
Z
Lerch
M M
MM
Chen
Z
Z
Xie
W
W
Ullrich
A
A
D000230:Adenocarcinoma / Q000235:genetics / Q000473:pathology; D000595:Amino Acid Sequence; D000951:Antigens, Neoplasm / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D015820:Cadherins / Q000378:metabolism; D002448:Cell Adhesion; D003001:Cloning, Molecular; D003598:Cytoskeletal Proteins / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D010190:Pancreatic Neoplasms / Q000235:genetics* / Q000473:pathology; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D015534:Trans-Activators; D014407:Tumor Cells, Cultured; D051176:beta Catenin
D000951:Antigens, Neoplasm; C495270:CTNNB1 protein, human; D015820:Cadherins; D003598:Cytoskeletal Proteins; D012333:RNA, Messenger; D015534:Trans-Activators; D051176:beta Catenin; C055984:mammary carcinoma antigen; D017027:Protein Tyrosine Phosphatases