In:
Journal of Cell Science, The Company of Biologists, Vol. 118, No. 22 ( 2005-11-15), p. 5231-5242
Abstract:
The ubiquitin proteasome system plays a fundamental role in the regulation of cellular processes by degradation of endogenous proteins. Proteasomes are localized in both, the cytoplasm and the cell nucleus, however, little is known about nuclear proteolysis. Here, fluorogenic precursor substrates enabled detection of proteasomal activity in nucleoplasmic cell fractions (turnover 0.0541 μM/minute) and nuclei of living cells (turnover 0.0472 μM/minute). By contrast, cell fractions of nucleoli or nuclear envelopes did not contain proteasomal activity. Microinjection of ectopic fluorogenic protein DQ-ovalbumin revealed that proteasomal protein degradation occurs in distinct nucleoplasmic foci, which partially overlap with signature proteins of subnuclear domains, such as splicing speckles or promyelocytic leukemia bodies, ubiquitin, nucleoplasmic proteasomes and RNA polymerase II. Our results establish proteasomal proteolysis as an intrinsic function of the cell nucleus.
Type of Medium:
Online Resource
ISSN:
1477-9137
,
0021-9533
Language:
English
Publisher:
The Company of Biologists
Publication Date:
2005
detail.hit.zdb_id:
219171-4
detail.hit.zdb_id:
1483099-1
SSG:
12
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