LDAF1 (lipid droplet assembly factor 1) is a conserved integral component of the lipid droplet biogenesis machinery that plays a central role in determining sites of lipid droplet (LD) formation 1. LDAF1 functions primarily through its interaction with seipin, forming an ~600 kDa oligomeric complex that serves as the core protein machinery for LD biogenesis at the endoplasmic reticulum 1. This complex defines specific ER domains where neutral lipids initially demix to form nascent lipid droplets; once LDs form, LDAF1 relocates from the complex to decorate the LD surface 1. Functionally, LDAF1 lowers the threshold for LD formation—in its absence, LDs form only at significantly elevated cellular triglyceride concentrations 1. Beyond biogenesis, LDAF1 acts as a multifunctional lipid droplet surface receptor that coordinates different aspects of the LD life cycle 2. This function is evolutionarily conserved across eukaryotes, with Drosophila and yeast homologs showing comparable roles in regulating LD size, number, and overall lipid storage 3. Clinically, LDAF1's role in LD biogenesis links it to lipid metabolism disorders and adipogenesis, though specific disease associations require further investigation.