Seipin is a key protein in the assembly of cytoplasmic lipid droplets (cLDs) and their maintenance at endoplasmic reticulum (ER)–LD junctions; the absence of seipin results in generalized lipodystrophy. How seipin mediates LD dynamics and prevents lipodystrophy are not well understood. New evidence suggests that seipin attracts triglyceride monomers from the ER to sites of droplet formation. By contrast, seipin may not be directly involved in the assembly of nuclear LDs and may actually suppress their formation at a distance. Seipin promotes adipogenesis, but lipodystrophy may also involve postadipogenic effects. We hypothesize that among these are a cycle of runaway lipolysis and lipotoxicity caused by aberrant LDs, resulting in a depletion of fat stores and a failure of adipose and other cells to thrive.

Seipin 是细胞质脂滴 (cLD) 组装及其在内质网 (ER)-LD 连接处维持的关键蛋白；缺乏 seipin 会导致全身性脂肪营养不良。seipin 如何介导 LD 动力学和预防脂肪营养不良尚不清楚。新的证据表明，seipin 将甘油三酯单体从 ER 吸引到液滴形成部位。相比之下，seipin 可能不直接参与核 LD 的组装，实际上可能会在一定距离内抑制它们的形成。Seipin 促进脂肪生成，但脂肪营养不良也可能涉及脂肪生成后效应。我们假设其中包括异常 LD 引起的失控脂肪分解和脂毒性循环，导致脂肪储存耗尽以及脂肪和其他细胞无法茁壮成长。