title: Overexpression of leukocyte marker CD43 causes activation of the tumor suppressor proteins p53 and ARF.
abstract: CD43 or leukosialin is a transmembrane sialoglycoprotein, whose extracellular domain participates in cell adhesiveness and the cytoplasmic tail regulates a variety of intracellular signal transduction pathways involved in cell proliferation. CD43 is abundantly expressed on the surface of hematopoietic cells, but CD43 expression is also frequently found in the tumor cells of nonhematopoietic origin. In the early stages of some tumors, the accumulation of tumor suppressor protein p53 has been described. Here, we show that the expression of CD43 causes the induction of functionally active p53 protein. Moreover, we found that the activation of p53 by CD43 is mediated by tumor suppressor protein ARF. The coexpression of CD43 and ARF in ARF-null mouse embryonic fibroblasts resulted in programmed cell death, but that was not the case when CD43 alone was expressed in these cells. These data provide the first evidence of the connection between p53- and CD43-dependent pathways.
authors.affiliation: Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, 23 Riia Street, Tartu 51010, Estonia. lkadaja@ebc.ee
authors.forename: Lilian
authors.initials: L
authors.lastname: Kadaja
authors.forename: Sirle
authors.initials: S
authors.lastname: Laos
authors.forename: Toivo
authors.initials: T
authors.lastname: Maimets
mesh_terms: D020823:ADP-Ribosylation Factor 1 / Q000235:genetics* / Q000378:metabolism*; D000230:Adenocarcinoma / Q000235:genetics / Q000473:pathology; D000818:Animals; D015703:Antigens, CD; D017209:Apoptosis; D015415:Biomarkers; D001943:Breast Neoplasms / Q000235:genetics / Q000473:pathology; D045744:Cell Line, Tumor; D004622:Embryo, Mammalian / Q000166:cytology; D005347:Fibroblasts / Q000378:metabolism; D016147:Genes, Tumor Suppressor; D006801:Humans; D051917:Leukosialin; D051379:Mice; D008954:Models, Biological; D012795:Sialoglycoproteins / Q000235:genetics* / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics* / Q000378:metabolism*
chemical_list: D015703:Antigens, CD; D015415:Biomarkers; D051917:Leukosialin; C465014:SPN protein, human; D012795:Sialoglycoproteins; C497863:Spn protein, mouse; D016159:Tumor Suppressor Protein p53; D020823:ADP-Ribosylation Factor 1