{
  "@type": "dcat:Dataset",
  "accessLevel": "public",
  "bureauCode": [
    "009:25"
  ],
  "contactPoint": {
    "@type": "vcard:Contact",
    "fn": "NIH",
    "hasEmail": "mailto:info@nih.gov"
  },
  "description": "Background\n          The mos proto-oncogene encodes a cytoplasmic serine/threonine-specific protein kinase with crucial function during meiotic cell division in vertebrates. Based on oncogenic amino acid substitutions the viral derivative, 124-v-Mos, displays constitutive protein kinase activity and functions independent of unknown upstream effectors of mos protein kinase. We have utilized this property of 124-v-Mos and screened for novel mos substrates in immunocomplex kinase assays in vitro.\n        \n        \n          Results\n          We generated recombinant 124-v-Mos using the baculovirus expression system in Spodoptera frugiperda cells and demonstrated constitutive kinase activity by the ability of 124-v-Mos to auto-phosphorylate and to phosphorylate vimentin, a known substrate of c-Mos. Using this approach we analyzed a panel of acidic and basic substrates in immunocomplex protein kinase assays and identified novel in vitro substrates for 124-v-Mos, the protein tyrosine phosphatase 1B (PTP1B), alpha-casein and beta-casein. We controlled mos-specific phosphorylation of PTP1B and casein in comparative assays using a synthetic kinase-inactive 124-v-Mos mutant and further, tryptic digests of mos-phosphorylated beta-casein identified a phosphopeptide specifically targeted by wild-type 124-v-Mos. Two-dimensional phosphoamino acid analyses showed that 124-v-mos targets serine and threonine residues for phosphorylation in casein at a 1:1 ratio but auto-phosphorylation occurs predominantly on serine residues.\n        \n        \n          Conclusion\n          The mos substrates identified in this study represent a basis to approach the identification of the mos-consensus phosphorylation motif, important for the development of specific inhibitors of the Mos protein kinase.",
  "distribution": [
    {
      "@type": "dcat:Distribution",
      "description": "Visit the original government dataset for complete information, documentation, and data access.",
      "downloadURL": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC102758/",
      "mediaType": "text/html",
      "title": "Official Government Data Source"
    }
  ],
  "identifier": "https://healthdata.gov/api/views/dwxj-4qj8",
  "issued": "2025-07-14",
  "keyword": [
    "enzyme-substrates",
    "kinase-assays",
    "mos-proto-oncogene",
    "nih",
    "protein-phosphorylation"
  ],
  "landingPage": "https://healthdata.gov/d/dwxj-4qj8",
  "modified": "2025-09-06",
  "programCode": [
    "009:033"
  ],
  "publisher": {
    "@type": "org:Organization",
    "name": "National Institutes of Health"
  },
  "theme": [
    "NIH"
  ],
  "title": "Identification of protein tyrosine phosphatase 1B and casein as substrates for 124-v-Mos"
}