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J Cell Sci. 2017 Oct 15;130(20):3467-3480. doi: 10.1242/jcs.203216. Epub 2017 Aug 24.

A PGAM5-KEAP1-Nrf2 complex is required for stress-induced mitochondrial retrograde trafficking.

Author information

1
Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73118, USA.
2
Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73118, USA.
3
Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73118, USA plafkers@omrf.org.
4
Department of Pathology, University of Irvine School of Medicine, Irvine, CA 92697, USA.

Abstract

The Nrf2 transcription factor is a master regulator of the cellular anti-stress response. A population of the transcription factor associates with the mitochondria through a complex with KEAP1 and the mitochondrial outer membrane histidine phosphatase, PGAM5. To determine the function of this mitochondrial complex, we knocked down each component and assessed mitochondrial morphology and distribution. We discovered that depletion of Nrf2 or PGAM5, but not KEAP1, inhibits mitochondrial retrograde trafficking induced by proteasome inhibition. Mechanistically, this disrupted motility results from aberrant degradation of Miro2, a mitochondrial GTPase that links mitochondria to microtubules. Rescue experiments demonstrate that this Miro2 degradation involves the KEAP1-cullin-3 E3 ubiquitin ligase and the proteasome. These data are consistent with a model in which an intact complex of PGAM5-KEAP1-Nrf2 preserves mitochondrial motility by suppressing dominant-negative KEAP1 activity. These data further provide a mechanistic explanation for how age-dependent declines in Nrf2 expression impact mitochondrial motility and induce functional deficits commonly linked to neurodegeneration.

KEYWORDS:

Clustering; Miro2; Mitochondria; Nrf2; Proteasome; Ubiquitin

PMID:
28839075
PMCID:
PMC5665445
DOI:
10.1242/jcs.203216
[Indexed for MEDLINE]
Free PMC Article

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