A RAB7A phosphoswitch coordinates Rubicon Homology protein regulation of Parkin-dependent mitophagy

Tudorica, DA; Basak, B; Puerta Cordova, AS; Khuu, G; Rose, K; Lazarou, M; Holzbaur, ELF; Hurley, JH

Author(s): Tudorica, DA; Basak, B; Puerta Cordova, AS; Khuu, G; Rose, K; Lazarou, M; Holzbaur, ELF; Hurley, JH;
Details: Publication Year 2024-07-01,Volume 223,Issue #7,Page e202309015
Journal Title: Journal of Cell Biology
Abstract: Activation of PINK1 and Parkin in response to mitochondrial damage initiates a response that includes phosphorylation of RAB7A at Ser72. Rubicon is a RAB7A binding negative regulator of autophagy. The structure of the Rubicon:RAB7A complex suggests that phosphorylation of RAB7A at Ser72 would block Rubicon binding. Indeed, in vitro phosphorylation of RAB7A by TBK1 abrogates Rubicon:RAB7A binding. Pacer, a positive regulator of autophagy, has an RH domain with a basic triad predicted to bind an introduced phosphate. Consistent with this, Pacer-RH binds to phosho-RAB7A but not to unphosphorylated RAB7A. In cells, mitochondrial depolarization reduces Rubicon:RAB7A colocalization whilst recruiting Pacer to phospho-RAB7A-positive puncta. Pacer knockout reduces Parkin mitophagy with little effect on bulk autophagy or Parkin-independent mitophagy. Rescue of Parkin-dependent mitophagy requires the intact pRAB7A phosphate-binding basic triad of Pacer. Together these structural and functional data support a model in which the TBK1-dependent phosphorylation of RAB7A serves as a switch, promoting mitophagy by relieving Rubicon inhibition and favoring Pacer activation.
Publisher: RUP
Keywords: *Mitophagy/genetics; Humans; *rab7 GTP-Binding Proteins; Phosphorylation; *Ubiquitin-Protein Ligases/metabolism/genetics; *Protein Serine-Threonine Kinases/metabolism/genetics; *rab GTP-Binding Proteins/metabolism/genetics; HeLa Cells; Protein Binding; Intracellular Signaling Peptides and Proteins/metabolism/genetics; Autophagy-Related Proteins/metabolism/genetics; Mitochondria/metabolism/genetics; HEK293 Cells
Research Division(s): Ubiquitin Signalling
PubMed ID: 38728007
Publisher's Version: https://doi.org/10.1083/jcb.202309015
Open Access at Publisher's Site: https://doi.org/10.1083/jcb.202309015
Terms of Use/Rights Notice: Refer to copyright notice on published article.

Creation Date: 2024-05-20 07:53:42

Last Modified: 2024-05-20 10:16:11