title: [Phosphorylation of proteasomes and alpha-RNP from rat liver cells].
abstract: In eukaryotic cells the population of proteasomes is heterogeneous. Here we have shown that proteasomes from nuclei and cytoplasm of rat liver cells differ in their subunit patterns. The subunit pattern of alpha-RNP differs from that of proteasomes, however, alpha-RNP particles contain the number of 26S proteasome subunits. Moreover, the proteasomes contain subunits of alpha-RNP. We have shown for the first time that nuclear proteasomes and alpha-RNP are hyperphosphorylated on threonine residues. Differences in phosphorylation state of subunits of nuclear and cytoplasmic proteasomes and alpha-RNP on threonine and tyrosine residues have been revealed. A suggestion is put forward that hyperphosphorylation of subunits may determine nuclear localization of these complexes in rat liver cells. The results obtained suggest that a highly specialized system of protein kinases and phosphatases may be involved in the regulation of phosphorylation state of different populations of proteasomes and alpha-RNP in rat liver cells.
authors.forename: A S
authors.initials: AS
authors.lastname: Tsimokha
authors.forename: Iu Ia
authors.initials: IuIa
authors.lastname: Vatazhok
authors.forename: E S
authors.initials: ES
authors.lastname: Vashukova
authors.forename: V A
authors.initials: VA
authors.lastname: Kulichkova
authors.forename: I V
authors.initials: IV
authors.lastname: Volkova
authors.forename: Iu B
authors.initials: IuB
authors.lastname: Ermolaeva
authors.forename: A G
authors.initials: AG
authors.lastname: Mittenberg
authors.forename: I N
authors.initials: IN
authors.lastname: Evteeva
authors.forename: V A
authors.initials: VA
authors.lastname: Ivanov
authors.forename: L N
authors.initials: LN
authors.lastname: Gauze
authors.forename: I M
authors.initials: IM
authors.lastname: Konstantinova
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000201:enzymology / Q000378:metabolism; D003593:Cytoplasm / Q000201:enzymology / Q000378:metabolism; D022781:Hepatocytes / Q000201:enzymology* / Q000378:metabolism; D008297:Male; D008970:Molecular Weight; D010766:Phosphorylation; D046988:Proteasome Endopeptidase Complex / Q000737:chemistry / Q000378:metabolism*; D051381:Rats; D012261:Ribonucleoproteins / Q000378:metabolism*; D013912:Threonine; D014443:Tyrosine
chemical_list: D012261:Ribonucleoproteins; D013912:Threonine; D014443:Tyrosine; D046988:Proteasome Endopeptidase Complex