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Expression and subcellular localization of mouse 20S proteasome activator complex PA28
Author(s) -
Soza Andrea,
Knuehl Christine,
Groettrup Marcus,
Henklein Peter,
Tanaka Keiji,
Kloetzel Peter-M.
Publication year - 1997
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/s0014-5793(97)00864-8
Subject(s) - nucleolus , cytoplasm , activator (genetics) , nucleus , messenger rna , microbiology and biotechnology , subcellular localization , cell fractionation , proteasome , spleen , northern blot , chemistry , western blot , biology , biochemistry , gene , enzyme , immunology
We have cloned the mouse PA28 proteasome activator cDNAs. Northern blot demonstrates high PA28 mRNA levels in liver, kidney and lung. mRNA levels are low in thymus, spleen and brain. In contrast, PA28 protein levels vary little between these tissues. Immunocytological analysis and cell fractionation experiments demonstrate that both subunits are almost equally distributed between the cytoplasm and the nucleus. Interestingly, PA28α spares nucleoli, while PA28β is strongly enhanced in the nucleolus. This indicates for the first time that the PA28α and PA28β subunits may serve nuclear functions which may be different from and independent of each other.