Phosphorylation and localization of protein-zero related (PZR) in cultured endothelial cells.
Protein-zero related (PZR) is an immunoglobulin V (IgV)-type immunoreceptor with two immunoreceptor tyrosine-based inhibitory motifs (ITIMs). PZR interacts with Src homology 2 domain-containing tyrosine phosphatase (SHP-2) via its tyrosine-phosphorylated ITIMs, for which c-Src is a putative kinase. Towards elucidating PZR function in endothelial cells (ECs), the authors cloned PZR from bovine aortic endothelial cells (BAECs) and characterized it. Mature bovine PZR had 94.8% and 92.7% sequence identity with canine and human proteins, respectively, and the two ITIM sequences were conserved among higher vertebrates. PZR was expressed in many cell types and was localized to cell contacts and intracellular granules in BAECs and mesothelioma (REN) cells. Coimmunoprecipitation revealed that PZR, Grb-2-associated binder-1 (Gab1), and platelet endothelial cell adhesion molecule-1 (PECAM-1) were three major SHP-2-binding proteins in BAECs. H(2)O(2) enhanced PZR tyrosine phosphorylation and PZR/SHP-2 interaction in ECs in a dose-and time-dependent manner. To see if tyrosine kinases other than Src are also capable of phosphorylating PZR, the authors cotransfected HEK293 cells with PZR and one of several tyrosine kinases and found that c-Src, c-Fyn, c-Lyn, Csk, and c-Abl, but not c-Fes, phosphorylated PZR and increased PZR/SHP-2 interaction. These results suggest that PZR is a cell adhesion protein that may be involved in SHP-2-dependent signaling at interendothelial cell contacts.
Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, Rochester, New York 14586, USA.
Ken-ichi
K
Kusano
Tamlyn N
TN
Thomas
Keigi
K
Fujiwara
D020816:Amino Acid Motifs; D000818:Animals; D001011:Aorta / Q000166:cytology; D001921:Brain / Q000098:blood supply; D002196:Capillaries / Q000166:cytology; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D002417:Cattle; D018929:Cell Culture Techniques; D002460:Cell Line; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D002645:Chickens; D017124:Conserved Sequence; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004622:Embryo, Mammalian; D042783:Endothelial Cells / Q000166:cytology* / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology; D005347:Fibroblasts / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007668:Kidney / Q000166:cytology; D051379:Mice; D008969:Molecular Sequence Data; D041681:NIH 3T3 Cells; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D010802:Phylogeny; D021382:Protein Sorting Signals; D017434:Protein Structure, Tertiary; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013347:Subcellular Fractions / Q000378:metabolism; D013997:Time Factors; D014162:Transfection; D014443:Tyrosine / Q000378:metabolism; D014471:Umbilical Veins / Q000166:cytology; D014680:Veins / Q000166:cytology; D018909:src Homology Domains
D002352:Carrier Proteins; D010750:Phosphoproteins; D021382:Protein Sorting Signals; D014443:Tyrosine; D006861:Hydrogen Peroxide; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases