The proteins encoded by c-akt and v-akt differ in post-translational modification, subcellular localization and oncogenic potential.

摘要: The acute retrovirus AKT8, isolated from an AKR mouse T-cell lymphoma, transforms mink lung cells in culture and is oncogenic when inoculated into newborn mice. oncogene carried by this virus, v-akt, arose recombination between Gag the 5' untranslated region of cellular gene c-akt. v-akt encodes a 105 kilodalton (kd) Gag-Akt fusion protein which phosphorylated on serine threonine residues. c-akt 55 kd serine-threonine protein-kinase, related to members kinase C (PKC) family contains SH2-like domain. catalytic domains Akt were expressed E. coli as fusions carboxy-terminus Maltose binding (MBP). Antibodies against these proteins raised rabbits they used determine potential myristylation subcellular localization products. Immunoprecipitation lysates [35S]methionine [3H]myristic acid labeled AKT8 transformed revealed that only was myristylated. Fractionation Dounce-homogenized extracts uninfected v-akt-transformed PA317 PC12 differential centrifugation showed while localized primarily cytosol (90%), dispersed among compartments with approximately 40% plasma membranes, 30% nucleus cytosol. To whether differences post-translational modification distribution translated oncogenicity two proteins, we based constructs express them both nontumorigenic rat T cell lymphoma line 5675. Intraperitoneal (IP) inoculation parental expressing 5675 nude Balb/c mice neither oncogenic. In sharp contrast results, found be highly