Biology subjects

Vosolsobe, S.

Publications and source records attributed to Vosolsobe, S..

3 recordsLinked to original sources

bioRxiv2024

Origin and evolution of Auxin Efflux Carrier family: PIN, PILS, GPR155 and the others

The resolution of the 3D structure of PIN proteins and the ability to universally predict protein structures using AlphaFold allowed us to reconsider the classification of Auxin efflux carriers within the BART superfamily, and we propose to merge members of this superfamily, possessing a characteristic fold with a helical crossover, with other families carrying this fold (BASS, NhaA, CPA and others) into a newly proposed superfamily named X-Helices Carriers (XHC). We further demonstrate a profound divergence between PIN and PILS proteins and monophyly of eukaryotic PINs with the animal cholesterol receptor GPR155/LYCHOS. We hypothesise that its signalling capacity is derived from a general feature of PIN proteins to interact with membrane lipids within the core membrane fold. Finally, we discuss the auxin-transport ability of PIN and PILS proteins in the context of the described properties of bacterial homologs that act as organic acid permeases. DisclaimerThis version is a draft and it will be updated during the next few weeks. HighlightsO_LIPINs are in plants and fragmentary in many algae and protists, but never in fungi C_LIO_LIEukaryotic PINs are monophyletic together with animal cholesterol receptor GPR155 C_LIO_LIPILS are frequently present in protists and in all fungi, but not in animals C_LIO_LIPINs/PILS split is occurred very early in Prokaryota C_LIO_LIAECs belongs to proposed superfamily of transporter with helical crossover C_LI

evolutionary biology↗

bioRxiv2023

Phytohormone profiling in an evolutionary framework

Multiple phytohormones act as conserved developmental regulators in land plants. Although the closely related streptophyte green algae typically lack full complements of molecular pathways underlying these responses, scattered reports of endogenous phytohormone production in these organisms exist. In this study, we performed a detailed LC/MS-based analysis of several phytohormones, their precursors and metabolites in all lineages of streptophyte algae. We also included chlorophyte algae and early-diverging land plants as outgroups. Free auxin, tRNA-derived cytokinins and certain phenolics including salicylic acid were found ubiquitously. However, land plants differed from green algae by the consistent detection of abscisic acid and the presence of auxin and cytokinin conjugates and trans-zeatin, supporting the hypotheses that these three phytohormones likely came to regulate development in the ancestral land plant. By contrast, we observed a patchy distribution of jasmonates among streptophytes. We additionaly analyzed the corresponding culture and empty media to account for phytohormone excretion and environmental contamination. Extracellular auxins and cytokinins were frequently detected, while agar constituted a major external source of phenolic compounds. We provide a highly comprehensive evolution-directed screen of phytohormone compound occurrence and thoroughly discuss our data in the context of current plant hormonomics and phylogenomics. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=143 SRC="FIGDIR/small/534998v1_ufig1.gif" ALT="Figure 1"> View larger version (52K): org.highwire.dtl.DTLVardef@1532f4org.highwire.dtl.DTLVardef@1c4396borg.highwire.dtl.DTLVardef@195d0eborg.highwire.dtl.DTLVardef@c71b11_HPS_FORMAT_FIGEXP M_FIG C_FIG

plant biology↗

bioRxiv2022

ARP2/3 complex associates with peroxisomes to participate in pexophagy in plants

ARP2/3 is a heteroheptameric protein complex evolutionary conserved in all eukaryotic organisms. Its conserved role is based on the induction of actin polymerization at the interface between membranes and the cytoplasm. Plant ARP2/3 has been reported to participate in actin reorganization at the plasma membrane during polarized growth of trichomes and at the plasma membrane-endoplasmic reticulum contact sites. We demonstrate here that individual plant subunits of ARP2/3 fused to fluorescent proteins form motile dot-like structures in the cytoplasm that are associated with plant peroxisomes. ARP2/3 dot structure is found at the peroxisome periphery and contains assembled ARP2/3 complex and WAVE/SCAR complex subunit NAP1. This dot occasionally colocalizes with the autophagosome, and under conditions that affect the autophagy, colocalization between ARP2/3 and the autophagosome increases. ARP2/3 subunits co-immunoprecipitate with ATG8f marker. Since mutants lacking functional ARP2/3 complex have more peroxisomes than WT, we link the ARP2/3 complex on peroxisomes to the process of peroxisome degradation by autophagy called pexophagy. Additionally, several other peroxisomal proteins colocalize with ARP2/3 dot on plant peroxisomes. Our results suggest a specific role of ARP2/3 and actin in the peroxisome periphery, presumably in membrane remodelling. We hypothesize that this role of ARP2/3 aids processes at the peroxisome periphery such as peroxisome degradation through autophagy or regulation of peroxisomal proteins localization or function. Significance statementARP2/3 complex-positive dots associate exclusively with peroxisomes in plant cells, where it colocalizes with autophagosome marker ATG8f and several other proteins. Our experiments link ARP2/3 to pexophagy: colocalization between ARP2/3 dots and autophagosome increases when autophagy processes are induced or inhibited; ARP2/3 and ATG8f colocalize and co-immunoprecipitate, and finally, ARP2/3 mutants cells contain more peroxisomes than WT. Our results suggest a novel role of ARP2/3 in peroxisome structure and function regulation.

cell biology↗