New friends for seipin - Implications of seipin partner proteins in the life cycle of lipid droplets.

Abstract Lipids act as building blocks for all cellular membranes and as key energy carriers. Neutral storage lipids are packaged into specialized organelles termed Lipid Droplets (LDs). LDs dynamically respond to the metabolic state of the cell, and undergo cycles of de novo biogenesis, growth, shrinkage, and consumption. How these processes are mediated on a molecular level is a key objective of the LD field. The yeast Lipid Droplet Organization (LDO) proteins and the human promethin/TMEM159/LDAF1 are newly identified molecular players involved in different aspects of the life cycle of LDs. These factors show remote homology to each other, and are physically and functionally linked to seipin, a central component in LD formation and adipogenesis.