Expression and subcellular localization of mouse 20S proteasome activator complex PA28.
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, PA28alpha spares nucleoli, while PA28beta is strongly enhanced in the nucleolus. This indicates for the first time that the PA28alpha and PA28beta subunits may serve nuclear functions which may be different from and independent of each other.
Soza
A
A
Institute for Biochemistry, Center of Experimental Medicine (ZEM), Medical Faculty (Charité), Humboldt University, Berlin, FRG.
Knuehl
C
C
Groettrup
M
M
Henklein
P
P
Tanaka
K
K
Kloetzel
P M
PM
D000595:Amino Acid Sequence; D000818:Animals; D001324:Autoantigens; D015152:Blotting, Northern; D001921:Brain / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism*; D002478:Cells, Cultured; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000378:metabolism*; D019084:Fluorescent Antibody Technique, Indirect; D007150:Immunohistochemistry; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D046988:Proteasome Endopeptidase Complex; D011506:Proteins / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013154:Spleen / Q000378:metabolism; D013950:Thymus Gland / Q000378:metabolism; D014018:Tissue Distribution
D001324:Autoantigens; C099558:Ki antigen; D011506:Proteins; D012333:RNA, Messenger; D046988:Proteasome Endopeptidase Complex