title: Cell-surface nucleolin is a signal transducing P-selectin binding protein for human colon carcinoma cells.
abstract: We have previously shown that P-selectin binding to Colo-320 human colon carcinoma cells induces specific activation of the alpha(5)beta(1) integrin with a concomitant increase of cell adhesion and spreading on fibronectin substrates in a phosphatidylinositol 3-kinase (PI3-K) and p38 MAPK-dependent manner. Here, we identified by affinity chromatography and characterized nucleolin as a P-selectin receptor on Colo-320 cells. Nucleolin mAb D3 significantly decreases the Colo-320 cell adhesion to immobilized P-selectin-IgG-Fc. Moreover, nucleolin becomes clustered at the external side of the plasma membrane of living, intact cells when bound to cross-linked P-selectin-IgG-Fc chimeric protein. We have also found P-selectin binding to Colo-320 cells induces tyrosine phosphorylation specifically of cell-surface nucleolin and formation of a signaling complex containing cell-surface nucleolin, PI3-K and p38 MAPK. Using siRNA approaches, we have found that both P-selectin binding to Colo-320 cells and formation of the P-selectin-mediated p38 MAPK/PI3-K signaling complex require nucleolin expression. These results show that nucleolin (or a nucleolin-like protein) is a signaling receptor for P-selectin on Colo-320 cells and suggest a mechanism for linkage of nucleolin to P-selectin-induced signal transduction pathways that regulate the adhesion and the spreading of Colo-320 on fibronectin substrates.
authors.affiliation: Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, NC 27709, USA.
authors.forename: E Merit
authors.initials: EM
authors.lastname: Reyes-Reyes
authors.forename: Steven K
authors.initials: SK
authors.lastname: Akiyama
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D051927:CD24 Antigen / Q000378:metabolism; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D003110:Colonic Neoplasms / Q000378:metabolism*; D006801:Humans; D007074:Immunoglobulin G / Q000235:genetics / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D019007:P-Selectin / Q000235:genetics / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D034622:RNA Interference; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D000097796:Nucleolin
chemical_list: D051927:CD24 Antigen; D007074:Immunoglobulin G; D008562:Membrane Glycoproteins; D019007:P-Selectin; D019869:Phosphatidylinositol 3-Kinases; D010750:Phosphoproteins; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D048051:p38 Mitogen-Activated Protein Kinases; D000097796:Nucleolin; C084882:P-selectin ligand protein