Degradation of Lipid Droplets in Plants and Algae—Right Time, Many Paths, One Goal

Abstract

In eukaryotic cells, lipids in the form of triacylglycerols (TAGs) are the major reservoir of cellular carbon and energy. These TAGs are packed into specialized organelles called lipid droplets (LDs). They can be found in most, if not all, types of cells, from bacteria to human. Recent data suggest that rather than being simple storage organelles, LDs are very dynamic structures at the center of cellular metabolism. This is also true in plants and algae, where LDs have been implicated in many processes including energy supply; membrane structure, function, trafficking; and signal transduction. Plant and algal LDs also play a vital role in human life, providing multiple sources of food and fuel. Thus, a lot of attention has been paid to metabolism and function of these organelles in recent years. This review summarizes the most recent advances on LDs degradation as a key process for TAGs release. While the initial knowledge on this process came from studies in oilseeds, the findings of the last decade revealed high complexity and specific mechanisms of LDs degradation in plants and algae. This includes identification of numerous novel proteins associated with LDs as well as a prominent role for autophagy in this process. This review outlines, systemizes, and discusses the most current data on LDs catabolism in plants and algae.

Multiplexed Genome Editing via an RNA Polymerase II Promoter-Driven sgRNA Array in the Diatom Phaeodactylum tricornutum: Insights Into the Role of StLDP

“…Lipid droplets can also be degraded by the autophagy-related lipophagy process ( Zienkiewicz and Zienkiewicz, 2020 ). It has recently been shown that the major LD surface protein of the eustigmatophyte Nannochloropsis oceanica interacts with the hallmark autophagy protein ATG8 during the autophagic catabolism of LDs ( Zienkiewicz et al, 2020 ).…”

The oleaginous astaxanthin-producing alga Chromochloris zofingiensis: potential from production to an emerging model for studying lipid metabolism and carotenogenesis

“…In addition to serving as a reservoir for neutral lipids, LD is believed to play roles in many biological processes, such as lipid homeostasis, signaling, membrane trafficking, etc. [ 213 – 215 ]. Proteomic studies of LD fraction, which help understand LD biology and lipid metabolism, have been conducted for many algae including C. reinhardtii [ 216 – 218 ], N. oceanica [ 219 ], Fistulifera sp.…”

Arabidopsis thaliana EARLY RESPONSIVE TO DEHYDRATION 7 Localizes to Lipid Droplets via Its Senescence Domain

“…Shown in Supplementary Dataset 3 are the summed LFQ and enrichment values for all detected proteins at different subcellular localizations based on PPDB (Sun et al, 2009;Ischebeck et al, 2020), including proteins annotated to be localized at LDs, which were the most enriched in the LD fractions, as expected. Among the other notable groups of proteins enriched in the LD fractions were those annotated to be localized to tonoplasts or vacuoles (Supplementary Dataset 3), which might reflect the LD-vacuole interactions that are proposed to occur during autophagic degradation of LDs in plants (Ischebeck et al, 2020;Zienkiewicz and Zienkiewicz, 2020), as well as proteins localized to lipid-storing plastoglobuli, which, like cytosolic LDs, are known to be upregulated during plant stress (Rottet et al, 2015;Lundquist et al, 2020).…”