Perilipin-related protein regulates lipid metabolism in C. elegans

Abstract

The perilipins are lipid droplet surface proteins that contribute to fat metabolism by controlling the access of lipids to lipolytic enzymes. Perilipins have been identified in organisms as diverse as metazoa, fungi, and amoebas but strikingly not in nematodes. Here we identify the protein encoded by the W01A8.1 gene in Caenorhabditis elegans as the closest homologue of metazoan perilipin. We demonstrate that nematode W01A8.1 is a cytoplasmic protein residing on lipid droplets. Human perilipins 1 and 2 localize in transgenic C. elegans on the same structures as proteins expressed from W01A8.1 gene. Inhibition and elimination of W01A8.1 affects the appearance of lipid droplets especially visible as the formation of large lipid droplets localized around the dividing nucleus during the early zygotic divisions. This phenomenon disappears in later stages of embryogenesis indicating the existence of an additional mechanism of lipid regulation in C. elegans. Our results demonstrate that perilipin-related regulation of fat metabolism is conserved in nematodes and provide new possibilities for functional studies of lipid metabolism.

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“…elegans. We have identified C. elegans locus W01A8.1 (previously annotated as mdt-28) as the sole PLIN gene orthologue in this nematode, henceforth labeled plin-1 (Chughtai et al 2015). Concurrently with our work, other groups have also independently identified this locus as a major LD protein influencing lipid metabolism (Na et al, 2015;Vrablik et al, 2015).…”

“…. The strain KV1 [plin-1 -/-] was prepared previously by Cas9/CRISPR-induced gene deletion (Chughtai et al 2015).…”

“…The pre-created externally acquired lines VS20, tm2369 and RD204 were crossed with KV1 to produce KV7, KV10 and KV2 respectively and VS20 was crossed with the newly obtained KV5 to produce KV6. Successful progenies of the crossed animals were screened by single-worm PCR (lines with no or weak fluorescence) as described previously (Chughtai et al 2015) or by fluorescent microscopy (strongly-fluorescent lines) and the final line was sequenced on target non-fluorescent locus to confirm genotype before further use. Primers used in single-worm PCRbased screening are listed in (Table S1).…”

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“…The wide expression pattern of F28F8.5 is also keeping with the data Based on the closest sequence similarity of F28F8.5 to MED28 that can be detected informatically in nematode genomes, conserved dual nuclear and cytoplasmic expression and involvement in a wide range of developmental processes, F28F8.5 is named (with WormBase approval) as MDT-28. W01A8.1, which was originally denominated also MDT-28 is renamed as PLIN-1 (Chughtai et al 2015). MED28 is a candidate Mediator complex subunit linking cytoplasmic structural signals towards the core of transcription regulation.…”

“…Although conserved between insects and mammals, a bona fide MED28 homologue had yet to be identified in nematodes. Our previous work showed that the protein previously identified as " in nematode and other databases is instead the nematode homologue of perilipin, a protein regulating lipid metabolism at the level of lipid droplets and is not related to MED28 (Chughtai et al 2015). Thinking it was unlikely that a MED28 homologue would be absent in nematode genomes, we searched for it using conserved features of MED28 orthologues from various phyla.…”