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Cellular distribution of cholesterogenesis‐linked, phosphoisoprenylated proteins in proliferating cells
Author(s) -
Sepp-Lorenzino Laura,
Azrolan Neal,
Coleman Peter S.
Publication year - 1989
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(89)80202-9
Subject(s) - distribution (mathematics) , microbiology and biotechnology , chemistry , biology , mathematics , mathematical analysis
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 [ 3 H]MVA and/or 32 P i 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 p I . 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.