Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK, 74078, USA.
Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK, 74078, USA.
Insect Biochem Mol Biol. 2019 Jul;110:69-79. doi: 10.1016/j.ibmb.2019.05.001. Epub 2019 May 2.
Perilipins (PLINs) are proteins that associate with lipid droplets (LDs) and play roles in the control of triglycerides (TG) metabolism. Two types of PLINs - 1 and 2- occur in insects. Following previous work on MsPLIN1A (a 42 kDa protein formerly called MsLsd1), here we report a new PLIN1 isoform, MsPLIN1B. MsPLIN1B cDNA was cloned and the 1835bp cDNA contains an ORF encoding a 47.9 kDa protein whose expression was confirmed by mass spectrometry. Alternative transcripts A and B, which differ in the alternative use of exon 1, were the most abundant PLIN1 transcripts in the fat body. These transcripts encode nearly identical proteins except that the B isoform contains 59 additional residues in its amino terminus. No conserved domain was identified in the extra region of MsPLIN1B. The novel PLIN1 isoform is found in lepidopteran species. In Manduca, PLIN1B was expressed only in the 5th instar larva and its levels correlated with fat storage. Furthermore, PLIN1B levels increased with the fat content of the diet in insects of the same age confirming a direct relationship between PLIN1B and TG storage irrespective of development. The nutritional status impacted PLIN1B levels, which decreased in starvation and increased with subsequent re-feeding. Altogether data support a link between PLIN1B and TG storage in caterpillars prior to pupation. The combined findings suggest distinct roles for PLIN1A, PLIN1B and PLIN2. MsPLIN1A abundance correlates with mobilization of TG stores, MsPLIN2 with the synthesis of new LDs and MsPLIN1B abundance correlates with high levels of TG storage and large LD sizes at the end of the last feeding period.
脂肪滴相关蛋白 (PLINs) 是与脂肪滴 (LDs) 结合并在控制甘油三酯 (TG) 代谢中发挥作用的蛋白质。两种类型的 PLINs-1 和 2-存在于昆虫中。在之前对 MsPLIN1A（一种 42kDa 蛋白，以前称为 MsLsd1）的研究之后，我们在这里报告了一种新的 PLIN1 同工型，MsPLIN1B。克隆了 MsPLIN1B cDNA，1835bp cDNA 包含一个编码 47.9kDa 蛋白的 ORF，该蛋白的表达通过质谱法得到证实。差异表达的剪接体 A 和 B 在第 1 外显子的选择性使用上存在差异，是脂肪体中最丰富的 PLIN1 转录本。这些转录本编码几乎相同的蛋白质，只是 B 同工型在其氨基末端含有 59 个额外的残基。在 MsPLIN1B 的额外区域未鉴定到保守结构域。新型 PLIN1 同工型存在于鳞翅目物种中。在 Manduca 中，PLIN1B 仅在 5 龄幼虫中表达，其水平与脂肪储存相关。此外，PLIN1B 水平随着同一龄期昆虫饮食中的脂肪含量增加而增加，证实了 PLIN1B 与 TG 储存之间的直接关系，而与发育无关。营养状况影响 PLIN1B 水平，饥饿时水平降低，随后再喂食时水平增加。总的来说，数据支持 PLIN1B 与化蛹前毛毛虫的 TG 储存之间存在联系。综合研究结果表明，PLIN1A、PLIN1B 和 PLIN2 具有不同的作用。MsPLIN1A 的丰度与 TG 储存的动员有关，MsPLIN2 与新 LD 的合成有关，而 MsPLIN1B 的丰度与最后一次喂养期结束时 TG 储存水平高和 LD 尺寸大有关。
