title: Activation of wild type p53 function by its mortalin-binding, cytoplasmically localizing carboxyl terminus peptides.
abstract: The Hsp70 family member mortalin (mot-2/mthsp70/GRP75) binds to a carboxyl terminus region of the tumor suppressor protein p53. By in vivo co-immunoprecipitation of mot-2 with p53 and its deletion mutants, we earlier mapped the mot-2-binding site of p53 to its carboxyl terminus 312-352 amino acid residues. In the present study we attempted to disrupt mot-2-p53 interactions by overexpression of short p53 carboxyl-terminal peptides. We report that p53 carboxyl-terminal peptides (amino acid residues 312-390, 312-352, 323-390, and 323-352) localize in the cytoplasm, whereas 312-322, 337-390, 337-352, and 352-390 locate mostly in the nucleus. Most interestingly, the cytoplasmically localizing p53 peptides harboring the residues 323-337 activated the endogenous p53 function by displacing it from p53-mortalin complexes and relocating it to the nucleus. Such activation of p53 function was sufficient to cause growth arrest of human osteosarcoma and breast carcinoma cells.
authors.affiliation: Gene Function Research Center, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba Science City 305-8562, Japan.
authors.forename: Sunil C
authors.initials: SC
authors.lastname: Kaul
authors.forename: Satoshi
authors.initials: S
authors.lastname: Aida
authors.forename: Tomoko
authors.initials: T
authors.lastname: Yaguchi
authors.forename: Kamaljit
authors.initials: K
authors.lastname: Kaur
authors.forename: Renu
authors.initials: R
authors.lastname: Wadhwa
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D005260:Female; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D051379:Mice; D024101:Mitochondrial Proteins; D012516:Osteosarcoma / Q000378:metabolism / Q000473:pathology; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion; D013347:Subcellular Fractions / Q000378:metabolism; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D018840:HSP70 Heat-Shock Proteins; C492001:HSPA9 protein, human; D024101:Mitochondrial Proteins; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; D016159:Tumor Suppressor Protein p53