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Cooperativity in Proteasome Core Particle Maturation

Authors :
Anjana Suppahia
Pushpa Itagi
Alicia Burris
Faith Mi Ge Kim
Alexander Vontz
Anupama Kante
Seonghoon Kim
Wonpil Im
Eric J. Deeds
Jeroen Roelofs
Source :
iScience, Vol 23, Iss 5, Pp - (2020)
Publication Year :
2020
Publisher :
Elsevier, 2020.

Abstract

Summary: Proteasomes are multi-subunit protease complexes found in all domains of life. The maturation of the core particle (CP), which harbors the active sites, involves dimerization of two half CPs (HPs) and an autocatalytic cleavage that removes β propeptides. How these steps are regulated remains poorly understood. Here, we used the Rhodococcus erythropolis CP to dissect this process in vitro. Our data show that propeptides regulate the dimerization of HPs through flexible loops we identified. Furthermore, N-terminal truncations of the propeptides accelerated HP dimerization and decelerated CP auto-activation. We identified cooperativity in autocatalysis and found that the propeptide can be partially cleaved by adjacent active sites, potentially aiding an otherwise strictly autocatalytic mechanism. We propose that cross-processing during bacterial CP maturation is the underlying mechanism leading to the observed cooperativity of activation. Our work suggests that the bacterial β propeptide plays an unexpected and complex role in regulating dimerization and autocatalytic activation.

Details

Language :
English
ISSN :
25890042
Volume :
23
Issue :
5
Database :
Directory of Open Access Journals
Journal :
iScience
Publication Type :
Academic Journal
Accession number :
edsdoj.0de08c6d4bbb465abfdd6328772e2069
Document Type :
article
Full Text :
https://doi.org/10.1016/j.isci.2020.101090