Actin-related protein (ARP2/3) complex 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. Here we demonstrate that individual plant subunits of ARP2/3 fused to fluorescent proteins form motile spot-like structures in the cytoplasm that are associated with peroxisomes in Arabidopsis and tobacco. ARP2/3 is found at the peroxisome periphery and contains the assembled ARP2/3 complex and the WAVE/SCAR complex subunit NAP1. This ARP2/3-positive peroxisomal domain 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 and peroxisome-associated ARP2/3 interact in vivo with the ATG8f marker. Since mutants lacking functional ARP2/3 complex have more peroxisomes than wild type, we suggest that ARP2/3 has a novel role in the process of peroxisome degradation by autophagy, called pexophagy.

• MeSH
• aktiny MeSH
• Arabidopsis * metabolismus   MeSH
• komplex proteinů 2-3 souvisejících s aktinem metabolismus   MeSH
• makroautofagie MeSH
• peroxizomy metabolismus   MeSH
• proteiny huseníčku * metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• aktiny MeSH
• komplex proteinů 2-3 souvisejících s aktinem MeSH
• proteiny huseníčku * MeSH

Microtubule organization and dynamics are critical for key developmental processes such as cell division, elongation, and morphogenesis. Microtubule severing is an essential regulator of microtubules and is exclusively executed by KATANIN 1 in Arabidopsis In this study, we comparatively studied the proteome-wide effects in two KATANIN 1 mutants. Thus, shotgun proteomic analysis of roots and aerial parts of single nucleotide mutant fra2 and T-DNA insertion mutant ktn1-2 was carried out. We have detected 42 proteins differentially abundant in both fra2 and ktn1-2 KATANIN 1 dysfunction altered the abundance of proteins involved in development, metabolism, and stress responses. The differential regulation of tubulins and microtubule-destabilizing protein MDP25 implied a feedback microtubule control in KATANIN 1 mutants. Furthermore, deregulation of profilin 1, actin-depolymerizing factor 3, and actin 7 was observed. These findings were confirmed by immunoblotting analysis of actin and by microscopic observation of actin filaments using fluorescently labeled phalloidin. Results obtained by quantitative RT-PCR analysis revealed that changed protein abundances were not a consequence of altered expression levels of corresponding genes in the mutants. In conclusion, we show that abundances of several cytoskeletal proteins as well as organization of microtubules and the actin cytoskeleton are amended in accordance with defective microtubule severing.

• MeSH
• aktiny metabolismus   MeSH
• anotace sekvence MeSH
• Arabidopsis genetika   metabolismus   MeSH
• biologie buňky * MeSH
• genová ontologie MeSH
• katanin genetika   MeSH
• mapy interakcí proteinů MeSH
• mikrotubuly metabolismus   MeSH
• mutace genetika   MeSH
• proteiny huseníčku genetika   metabolismus   MeSH
• proteom metabolismus   MeSH
• proteomika metody   MeSH
• rostlinné geny MeSH
• zpětná vazba fyziologická * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• aktiny MeSH
• katanin MeSH
• KTN1 protein, Arabidopsis MeSH Prohlížeč
• proteiny huseníčku MeSH
• proteom MeSH

BACKGROUND: Somatic embryogenesis in spruce is a process of high importance for biotechnology, yet it comprises of orchestrated series of events whose cellular and molecular details are not well understood. In this study, we examined the role of actin cytoskeleton during somatic embryogenesis in Norway spruce line AFO 541 by means of anti-actin drugs. RESULTS: Application of low doses (50-100 nM) of latrunculin B (Lat B) during the maturation of somatic embryos predominantly killed suspensor cells while leaving the cells in meristematic centres alive, indicating differential sensitivity of actin in the two cell types. The treatment resulted in faster development of more advanced embryos into mature somatic embryos and elimination of insufficiently developed ones. In searching for the cause of the differential actin sensitivity of the two cell types, we analysed the composition of actin isoforms in the culture and isolated four spruce actin genes. Analysis of their expression during embryo maturation revealed that one actin isoform was expressed constitutively in both cell types, whereas three actin isoforms were expressed predominantly in suspensor cells and their expression declined during the maturation. The expression decline was greatly enhanced by Lat B treatment. Sequence analysis revealed amino-acid substitutions in the Lat B-binding site in one of the suspensor-specific actin isoforms, which may result in a different binding affinity for Lat B. CONCLUSIONS: We show that manipulating actin in specific cell types in somatic embryos using Lat B treatment accelerated and even synchronized the development of somatic embryos and may be of practical use in biotechnology.

• MeSH
• aktiny antagonisté a inhibitory   metabolismus   MeSH
• bicyklické sloučeniny heterocyklické farmakologie   MeSH
• cytoskelet účinky léků   MeSH
• embryonální vývoj MeSH
• fylogeneze MeSH
• protein - isoformy metabolismus   MeSH
• regulace genové exprese u rostlin MeSH
• RNA rostlin genetika   MeSH
• rostlinné geny MeSH
• sekvenční seřazení MeSH
• smrk embryologie   růst a vývoj   MeSH
• substituce aminokyselin MeSH
• techniky tkáňových kultur MeSH
• thiazolidiny farmakologie   MeSH
• vazebná místa MeSH
• vývojová regulace genové exprese MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• aktiny MeSH
• bicyklické sloučeniny heterocyklické MeSH
• latrunculin B MeSH Prohlížeč
• protein - isoformy MeSH
• RNA rostlin MeSH
• thiazolidiny MeSH