Mammalian 26S proteasomes remain intact during protein degradation

Franziska Kriegenburg; Michael Seeger; Yasushi Saeki; Keiji Tanaka; Anne-Marie B Lauridsen; Rasmus Hartmann-Petersen; Klavs B Hendil

doi:10.1016/j.cell.2008.08.032

Mammalian 26S proteasomes remain intact during protein degradation

Franziska Kriegenburg, Michael Seeger, Yasushi Saeki, Keiji Tanaka, Anne-Marie B Lauridsen, Rasmus Hartmann-Petersen, Klavs B Hendil

Biomolecular Sciences

31 Citations (Scopus)

Abstract

It has been suggested that degradation of polyubiquitylated proteins is coupled to dissociation of 26S proteasomes. In contrast, using several independent types of experiments, we find that mammalian proteasomes can degrade polyubiquitylated proteins without disassembling. Thus, immobilized, (35)S-labeled 26S proteasomes degraded polyubiquitylated Sic1 and c-IAP1 without releasing any subunits. In addition, it is predicted that if 26S proteasomes dissociate into 20S proteasomes and regulatory complexes during a degradation cycle, the reassembly rate would be limiting at low proteasome concentrations. However, the rate with which each proteasome degraded polyubiquitylated Sic1 was independent of the proteasome concentration. Likewise, substrate-dependent dissociation of 26S proteasomes could not be detected by nondenaturing electrophoresis. Lastly, epoxomicin-inhibited 20S proteasomes can trap released regulatory complexes, forming inactive 26S proteasomes, but addition of epoxomicin-inhibited 20S proteasomes had no effect on the degradation of either polyubiquitylated Sic1 or UbcH10 by 26S proteasomes or of endogenous substrates in cell extracts.

Original language	English
Journal	Cell
Volume	135
Issue number	2
Pages (from-to)	355-65
Number of pages	10
ISSN	0092-8674
DOIs	https://doi.org/10.1016/j.cell.2008.08.032
Publication status	Published - 2008

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10.1016/j.cell.2008.08.032

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@article{2e1deb60dee611ddb5fc000ea68e967b,

title = "Mammalian 26S proteasomes remain intact during protein degradation",

abstract = "It has been suggested that degradation of polyubiquitylated proteins is coupled to dissociation of 26S proteasomes. In contrast, using several independent types of experiments, we find that mammalian proteasomes can degrade polyubiquitylated proteins without disassembling. Thus, immobilized, (35)S-labeled 26S proteasomes degraded polyubiquitylated Sic1 and c-IAP1 without releasing any subunits. In addition, it is predicted that if 26S proteasomes dissociate into 20S proteasomes and regulatory complexes during a degradation cycle, the reassembly rate would be limiting at low proteasome concentrations. However, the rate with which each proteasome degraded polyubiquitylated Sic1 was independent of the proteasome concentration. Likewise, substrate-dependent dissociation of 26S proteasomes could not be detected by nondenaturing electrophoresis. Lastly, epoxomicin-inhibited 20S proteasomes can trap released regulatory complexes, forming inactive 26S proteasomes, but addition of epoxomicin-inhibited 20S proteasomes had no effect on the degradation of either polyubiquitylated Sic1 or UbcH10 by 26S proteasomes or of endogenous substrates in cell extracts.",

author = "Franziska Kriegenburg and Michael Seeger and Yasushi Saeki and Keiji Tanaka and Lauridsen, {Anne-Marie B} and Rasmus Hartmann-Petersen and Hendil, {Klavs B}",

note = "Keywords: Animals; Cattle; Cell Line; Hela Cells; Humans; Proteasome Endopeptidase Complex; Proto-Oncogene Protein c-fli-1; Ubiquitin",

year = "2008",

doi = "10.1016/j.cell.2008.08.032",

language = "English",

volume = "135",

pages = "355--65",

journal = "Cell",

issn = "0092-8674",

publisher = "Cell Press",

number = "2",

}

TY - JOUR

T1 - Mammalian 26S proteasomes remain intact during protein degradation

AU - Kriegenburg, Franziska

AU - Seeger, Michael

AU - Saeki, Yasushi

AU - Tanaka, Keiji

AU - Lauridsen, Anne-Marie B

AU - Hartmann-Petersen, Rasmus

AU - Hendil, Klavs B

N1 - Keywords: Animals; Cattle; Cell Line; Hela Cells; Humans; Proteasome Endopeptidase Complex; Proto-Oncogene Protein c-fli-1; Ubiquitin

PY - 2008

Y1 - 2008

N2 - It has been suggested that degradation of polyubiquitylated proteins is coupled to dissociation of 26S proteasomes. In contrast, using several independent types of experiments, we find that mammalian proteasomes can degrade polyubiquitylated proteins without disassembling. Thus, immobilized, (35)S-labeled 26S proteasomes degraded polyubiquitylated Sic1 and c-IAP1 without releasing any subunits. In addition, it is predicted that if 26S proteasomes dissociate into 20S proteasomes and regulatory complexes during a degradation cycle, the reassembly rate would be limiting at low proteasome concentrations. However, the rate with which each proteasome degraded polyubiquitylated Sic1 was independent of the proteasome concentration. Likewise, substrate-dependent dissociation of 26S proteasomes could not be detected by nondenaturing electrophoresis. Lastly, epoxomicin-inhibited 20S proteasomes can trap released regulatory complexes, forming inactive 26S proteasomes, but addition of epoxomicin-inhibited 20S proteasomes had no effect on the degradation of either polyubiquitylated Sic1 or UbcH10 by 26S proteasomes or of endogenous substrates in cell extracts.

AB - It has been suggested that degradation of polyubiquitylated proteins is coupled to dissociation of 26S proteasomes. In contrast, using several independent types of experiments, we find that mammalian proteasomes can degrade polyubiquitylated proteins without disassembling. Thus, immobilized, (35)S-labeled 26S proteasomes degraded polyubiquitylated Sic1 and c-IAP1 without releasing any subunits. In addition, it is predicted that if 26S proteasomes dissociate into 20S proteasomes and regulatory complexes during a degradation cycle, the reassembly rate would be limiting at low proteasome concentrations. However, the rate with which each proteasome degraded polyubiquitylated Sic1 was independent of the proteasome concentration. Likewise, substrate-dependent dissociation of 26S proteasomes could not be detected by nondenaturing electrophoresis. Lastly, epoxomicin-inhibited 20S proteasomes can trap released regulatory complexes, forming inactive 26S proteasomes, but addition of epoxomicin-inhibited 20S proteasomes had no effect on the degradation of either polyubiquitylated Sic1 or UbcH10 by 26S proteasomes or of endogenous substrates in cell extracts.

U2 - 10.1016/j.cell.2008.08.032

DO - 10.1016/j.cell.2008.08.032

M3 - Journal article

C2 - 18957208

SN - 0092-8674

VL - 135

SP - 355

EP - 365

JO - Cell

JF - Cell

IS - 2

ER -

Mammalian 26S proteasomes remain intact during protein degradation

Abstract

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