The human lipodystrophy protein seipin is an ER membrane adaptor for the adipogenic PA phosphatase lipin 1.

Abstract

Disruption of the gene BSCL2 causes a severe, generalised lipodystrophy, demonstrating the critical role of its protein product, seipin, in human adipose tissue development. Seipin is essential for adipocyte differentiation, whilst the study of seipin in non-adipose cells has suggested a role in lipid droplet formation. However, its precise molecular function remains poorly understood. Here we demonstrate that seipin can inducibly bind lipin 1, a phosphatidic acid (PA) phosphatase important for lipid synthesis and adipogenesis. Knockdown of seipin during early adipogenesis decreases the association of lipin 1 with membranes and increases the accumulation of its substrate PA. Conversely, PA levels are reduced in differentiating cells by overexpression of wild-type seipin but not by expression of a mutated seipin that is unable to bind lipin 1. Together our data identify lipin as the first example of a seipin-interacting protein and reveals a novel molecular function for seipin in developing adipocytes.

• Authors: M F Michelle Sim, Rowena J Dennis, Evelyne M Aubry, Nardev Ramanathan, Hiroshi Sembongi, Vladimir Saudek, Daisuke Ito, Stephen O'Rahilly, Symeon Siniossoglou, Justin J Rochford
• Journal: Molecular metabolism (Mol Metab) Vol. 2 Issue 1 Pg. 38-46 ( 2012) ISSN: 2212-8778 [Print] Germany
• PMID: 24024128 (Publication Type: Journal Article)