Localisation of 26S proteasomes with different subunit composition in insect muscles undergoing programmed cell death.
The 26S proteasome is a large multisubunit complex involved in degrading both cytoplasmic and nuclear proteins. We have investigated the subcellular distribution of four regulatory ATPase subunits (S6 (TBP7/MS73), S6' (TBP1), S7 (MSS1), and S10b (SUG2)) together with components of 20S proteasomes in the intersegmental muscles (ISM) of Manduca sexta during developmentally programmed cell death (PCD). Immunogold electron microscopy shows that S6 is located in the heterochromatic part of nuclei of ISM fibres. S6' is present in degraded material only outside intact fibres. S7 can be detected in nuclei, cytoplasm and also in degraded material. S10b, on the other hand, is initially found in nuclei and subsequently in degraded cytoplasmic locations during PCD. 20S proteasomes are present in all areas where ATPase subunits are detected, consistent with the presence of intact 26S proteasomes. These results are discussed in terms of heterogeneity of 26S proteasomes, 26S proteasome disassembly and the possible role of ATPases in non-proteasome complexes in the process of PCD. Cell Death and Differentiation (2000) 7, 1210 - 1217.
Löw
P
P
Department of General Zoology, Eötvös University, Budapest, Hungary. peterlow@cerebus.elte.hu
Hastings
R A
RA
Dawson
S P
SP
Sass
M
M
Billett
M A
MA
Mayer
R J
RJ
Reynolds
S E
SE
D000074183:ATPases Associated with Diverse Cellular Activities; D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D002352:Carrier Proteins / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D033862:Iron-Binding Proteins; D018402:Manduca / Q000378:metabolism; D008854:Microscopy, Electron; D018482:Muscle, Skeletal / Q000201:enzymology* / Q000648:ultrastructure; D010447:Peptide Hydrolases / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors / Q000378:metabolism; D033863:Transferrin-Binding Proteins
D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D033862:Iron-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D033863:Transferrin-Binding Proteins; C075363:PSMC2 protein, human; D010447:Peptide Hydrolases; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease; D000251:Adenosine Triphosphatases; C103015:RPT4 protein, S cerevisiae; D000074183:ATPases Associated with Diverse Cellular Activities