title: Valosin containing protein (VCP/p97) is a novel substrate for the protein tyrosine phosphatase PTPL1.
abstract: Identification of Protein Tyrosine Phosphatase (PTP) substrates is critical in understanding cellular role in normal cells as well as cancer cells. We have previously shown that reduction of PTPL1 protein levels in Ewings sarcoma (ES) inhibit cell growth and tumorigenesis. Therefore, we sought to identify novel PTPL1 substrates that may be important for tumorigenesis. In this current work, we demonstrated that mouse embryonic fibroblasts without PTPL1 catalytic activity fail to form foci when transfected with oncogenes. We proved that catalytic activity of PTPL1 is important for ES cell growth. Using a substrate-trapping mutant of PTPL1 we identified putative PTPL1 substrates by mass-spectrometry. One of these putative substrates was characterized as Valosin Containing Protein (VCP/p97). Using multiple biochemical assays we validated VCP as a novel substrate of PTPL1. We also provide evidence that tyrosine phosphorylation of VCP might be important for its midbody localization during cytokinesis. In conclusion, our work identifies VCP as a new substrate for PTPL1, which may be important in cellular transformation. Our investigation link an oncogenic transcription factor EWS-FLI1, with a key transcriptional target protein tyrosine phosphatase PTPL1, and its substrate VCP. Given our observation that PTPL1 catalytic activity is important for cell transformation, our results may also suggest that VCP regulation by PTPL1 might be important for tumorigenesis.
authors.affiliation: Departments of Oncology and Pediatrics, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC 20057, USA. oda@georgetown.edu
authors.forename: Ogan D
authors.initials: OD
authors.lastname: Abaan
authors.forename: Wiljan
authors.initials: W
authors.lastname: Hendriks
authors.forename: Aykut
authors.initials: A
authors.lastname: Uren
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Toretsky
authors.forename: Hayriye V
authors.initials: HV
authors.lastname: Erkizan
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001859:Bone Neoplasms / Q000201:enzymology / Q000473:pathology; D002384:Catalysis; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D002471:Cell Transformation, Neoplastic / Q000378:metabolism* / Q000473:pathology*; D002478:Cells, Cultured; D005347:Fibroblasts; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D008817:Mice, Mutant Strains; D010190:Pancreatic Neoplasms / Q000201:enzymology / Q000473:pathology; D054595:Protein Tyrosine Phosphatase, Non-Receptor Type 13 / Q000235:genetics / Q000378:metabolism*; D012512:Sarcoma, Ewing / Q000201:enzymology / Q000473:pathology; D013379:Substrate Specificity / Q000502:physiology; D000074405:Valosin Containing Protein
chemical_list: D018797:Cell Cycle Proteins; D054595:Protein Tyrosine Phosphatase, Non-Receptor Type 13; C516743:Ptpn13 protein, mouse; D000251:Adenosine Triphosphatases; C000614178:VCP protein, human; D000074405:Valosin Containing Protein; C000614179:Vcp protein, mouse