Simultaneous Visualization of Peroxisomes and Cytoskeletal Elements Reveals Actin and Not Microtubule-Based Peroxisome Motility in Plants,

Abstract

Peroxisomes were visualized in living plant cells using a yellow fluorescent protein tagged with a peroxisomal targeting signal consisting of the SKL motif. Simultaneous visualization of peroxisomes and microfilaments/microtubules was accomplished in onion (Allium cepa) epidermal cells transiently expressing the yellow fluorescent protein-peroxi construct, a green fluorescent protein-mTalin construct that labels filamentous-actin filaments, and a green fluorescent proteinmicrotubule-binding domain construct that labels microtubules. The covisualization of peroxisomes and cytoskeletal elements revealed that, contrary to the reports from animal cells, peroxisomes in plants appear to associate with actin filaments and not microtubules. That peroxisome movement is actin based was shown by pharmacological studies. For this analysis we used onion epidermal cells and various cell types of Arabidopsis including trichomes, root hairs, and root cortex cells exhibiting different modes of growth. In transient onion epidermis assay and in transgenic Arabidopsis plants, an interference with the actin cytoskeleton resulted in progressive loss of saltatory movement followed by the aggregation and a complete cessation of peroxisome motility within 30 min of drug application. Microtubule depolymerization or stabilization had no effect.

Barley MLO Modulates Actin-Dependent and Actin-Independent Antifungal Defense Pathways at the Cell Periphery

“…The latter was frequently associated with the formation of peroxisome aggregates ( Fig. 2D; Supplemental Video S4), which is consistent with previously reported effects on organelle motility by pharmacological actin cytoskeleton interference (Mathur et al, 2002). Despite this drastic perturbation of organelle motility and actin cytoskeleton architecture, affected cells remained alive because individual peroxisomes still exhibited few saltatory movements (Supplemental Video S4).…”

“…and Chua, 2002;Mano et al, 2002;Mathur et al, 2002). We expressed a GFP variant with a C-terminal peroxisomal targeting sequence (GFP-PTS1; see ''Materials and Methods'') with or without HvADF3 in barley leaf epidermal cells and studied peroxisomal movement by epifluorescence microscopy at 60 h after particle bombardment.…”

FRIENDLY Regulates Mitochondrial Distribution, Fusion, and Quality Control in Arabidopsis

“…This apparent stickiness of mitochondria in the absence of their actin scaffold is not observed with other organelles that move on actin. For example, while peroxisomes and Golgi bodies move on actin and latrunculin B arrests this movement, neither organelle forms large clusters in response to actin depolymerization (Nebenführ et al, 1999;Brandizzi et al, 2002;Mano et al, 2002;Mathur et al, 2002;Sparkes et al, 2008). Furthermore, the clustering of mitochondria in friendly is not due to a general cytoskeletal or motor defect, since the distribution and movement of peroxisomes are not affected in the mutant (Supplemental Fig.…”

Getting a camel through the eye of a needle: the import of folded proteins by peroxisomes

“…As well as arising from the ER, peroxisomes can proliferate, divide and be partitioned between daughter cells during division (Motley and Hettema, 2007;Fagarasanu et al, 2009). Peroxisomes are dynamic organelles which move on the actin-myosin system in plants (Mathur et al, 2002) and yeast (Fagarasanu et al, 2009), and on microtubules in mammals (Schrader et al, 2000). Consistent with the ability to be derived from the ER membrane, peroxisomes appear to have been an 'invention' of eukaryotic cells (Schluter et al, 2006) and are found in almost all eukaryotes.…”