The Arabidopsis Chloroplast Division Protein DYNAMIN-RELATED PROTEIN5B Also Mediates Peroxisome Division

Abstract

Peroxisomes are highly dynamic organelles involved in various metabolic pathways. The division of peroxisomes is regulated by factors such as the PEROXIN11 (PEX11) proteins that promote peroxisome elongation and the dynamin-related proteins (DRPs) and FISSION1 (FIS1) proteins that function together to mediate organelle fission. In Arabidopsis thaliana, DRP3A/DRP3B and FIS1A (BIGYIN)/FIS1B are two pairs of homologous proteins known to function in both peroxisomal and mitochondrial division. Here, we report that DRP5B, a DRP distantly related to the DRP3s and originally identified as a chloroplast division protein, also contributes to peroxisome division. DRP5B localizes to both peroxisomes and chloroplasts. Mutations in the DRP5B gene lead to peroxisome division defects and compromised peroxisome functions. Using coimmunoprecipitation and bimolecular fluorescence complementation assays, we further demonstrate that DRP5B can interact or form a complex with itself and with DRP3A, DRP3B, FIS1A, and most of the Arabidopsis PEX11 isoforms. Our data suggest that, in contrast with DRP3A and DRP3B, whose orthologs exist across plant, fungal, and animal kingdoms, DRP5B is a plant/algal invention to facilitate the division of their organelles (i.e., chloroplasts and peroxisomes). In addition, our results support the notion that proteins involved in the early (elongation) and late (fission) stages of peroxisome division may act cooperatively.

E3 ubiquitin ligase SP1 regulates peroxisome biogenesis in Arabidopsis

“…Hence, developmental or environmental cues that induce changes in the chloroplast proteome may also trigger proteome adjustment of the peroxisome. This notion is particularly interesting, given that these two organelles also share a major component of the division machinery, the dynamin-like GTPase DRP5B (55). Thus, both the organelle division and the protein import processes of peroxisomes and chloroplasts share key factors that ultimately may contribute to their linked metabolism.…”

Phosphatidylinositol 4-Phosphate Negatively Regulates Chloroplast Division in Arabidopsis

“…Chloroplast membranes contain neither PS nor CL (Douce and Joyard, 1990); thus, they would not be targets for DRP5B binding on the chloroplast membrane. Because DRP5B localizes to peroxisomes (Zhang and Hu, 2010) as well as chloroplasts, and peroxisome membranes probably contain PS, DRP5B may bind to PS on peroxisome membranes. In this study, we focused on the functions of PI4P, which interacts with PDV1 and PDV2, in chloroplast division.…”

Plant Peroxisomes: Biogenesis and Function

“…The closely related DRP3A and DRP3B proteins are dual localized and shared by peroxisomal and mitochondrial divisions, with DRP3A playing a major role in peroxisome fission (Mano et al, 2004;Fujimoto et al, 2009;Zhang and Hu, 2009;Kaur and Hu, 2009 and references therein) (Figure 2). Interestingly, DRP5B (ARC5), a DRP distantly related to DRP3, targets to chloroplasts and peroxisomes and facilitates the division of both organelles (Gao et al, 2003;Zhang and Hu, 2010) (Figure 2). Besides having enlarged, dumbbell-shaped chloroplasts, drp5B mutants also contain aggregated peroxisomes that are impaired in fission ( Figure 2B) and are partially compromised in peroxisomal functions .…”