Peroxisome Dynamics in Cultured Mammalian Cells

Abstract

Despite the identification and characterization of various proteins that are essential for peroxisome biogenesis, the origin and the turnover of peroxisomes are still unresolved critical issues. In this study, we used the HaloTag technology as a new approach to examine peroxisome dynamics in cultured mammalian cells. This technology is based on the formation of a covalent bond between the HaloTag protein-a mutated bacterial dehalogenase which is fused to the protein of interest-and a synthetic haloalkane ligand that contains a fluorophore or affinity tag. By using cell-permeable ligands of distinct fluorescence, it is possible to image distinct pools of newly synthesized proteins, generated from a single genetic HaloTag-containing construct, at different wavelengths. Here, we show that peroxisomes display an age-related heterogeneity with respect to their capacity to incorporate newly synthesized proteins. We also demonstrate that these organelles do not exchange their protein content. In addition, we present evidence that the matrix protein content of preexisting peroxisomes is not evenly distributed over new organelles. Finally, we show that peroxisomes in cultured mammalian cells, under basal growth conditions, have a half-life of approximately 2 days and are mainly degraded by an autophagy-related mechanism. The implications of these findings are discussed.

The Ether Lipid Precursor Hexadecylglycerol Stimulates the Release and Changes the Composition of Exosomes Derived from PC-3 Cells

“…In these cells, exosome release was slightly reduced. However, we have to consider that the levels of this enzyme were only depleted by ϳ70%, probably due to the long half-life of peroxisomes and of this enzyme (50,51). The release of exosomes is the end point of a process that can be divided into several steps.…”

Peroxisomes and Kidney Injury

“…This constant turnover is essential for preservation of cellular and organellar competence. Experimental studies demonstrated that peroxisomes have a half-life of circa 48 h under basal conditions and are primarily degraded by autophagy (44). Autophagy is a highly conserved lysosome-dependent pathway that maintains the quality of cellular components through continual removal of redundant or damaged proteins or entire organelles (72).…”

PEX11 proteins attract Mff and hFis1 to coordinate peroxisomal fission

“…Accordingly, the peroxisomal compartment adapts to changes in cellular microenvironments through proliferation and specific degradation (Fagarasanu et al, 2007;Oku and Sakai, 2010). Studies on peroxisome turnover in mammalian cells revealed a half-life of about two days (de Duve et al, 1974;Huybrechts et al, 2009). To guarantee the maintenance of peroxisomes under varying conditions, mechanisms exist that insure their steadystate either by growth and division of pre-existing organelles or via de novo biogenesis from the endoplasmic reticulum (Geuze et al, 2003;Motley and Hettema, 2007;Toro et al, 2007;Toro et al, 2009).…”