Cellular distribution of cholesterogenesis-linked, phosphoisoprenylated proteins in proliferating cells.
A set of isoprenylated proteins has been detected in rapidly proliferating, suspension-grown murine lymphoma cells. Our evidence indicates that all of these isoprenylated proteins are phosphorylated. Subsequent to a 24 h incubation with mevinolin to deplete the intracellular mevalonate (MVA) level, cells were incubated with [3H]MVA and/or 32Pi and both total cell and subcellular fraction proteins were resolved via 1- and 2-D gel electrophoresis, then assessed via subsequent autoradiography. The phospho-isoprenylated proteins comprise a set spanning a molecular mass range of 21-69 kDa and all dispay acidic pI. MVA-derivatized proteins of 21-24 kDa, which consist of multiple isoforms, are present in both cytosolic and nuclear fractions. Larger phospho-isoprenylated protein species (44-69 kDa) are specifically localized within the nucleus, where applicable extraction protocols indicate that they are part of or closely affiliated with the nuclear matrix-intermediate filament (NM-IF) components. The localization of the 69 kDa prenylated species within the NM-IF fraction, together with evidence of its phosphorylation, supports recent indications that this protein is the nuclear matrix component lamin B.
Sepp-Lorenzino
L
L
Dept of Biology, New York University, NY 10003.
Azrolan
N
N
Coleman
P S
PS
D000818:Animals; D002455:Cell Division; D002467:Cell Nucleus / Q000378:metabolism; D002784:Cholesterol / Q000096:biosynthesis*; D003600:Cytosol / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D007382:Intermediate Filaments / Q000378:metabolism; D007526:Isoelectric Point; D008148:Lovastatin / Q000494:pharmacology; D008223:Lymphoma; D008798:Mevalonic Acid / Q000378:metabolism; D051379:Mice; D008970:Molecular Weight; D010710:Phosphates / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism*; D011106:Polyisoprenyl Phosphates / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D010710:Phosphates; D010750:Phosphoproteins; D011106:Polyisoprenyl Phosphates; D002784:Cholesterol; D008148:Lovastatin; D008798:Mevalonic Acid