Table 1. Overview of key factors of lipid droplet biogenesis.

Yeast	Mammals	Protein Function	Key Reference
A. Key LD biogenesis proteins from yeast and mammals
Sei1	Seipin	Defines sites of LD biogenesis in the ER by sequestering DAG/TAG in its toroidal rings, facilitates flow of TAG between LDs	[33,37–39,42,43]
Ldb16	–	Yeast-specific subunit of Seipin	[36,41]
Ldo16/Ldo45	LDAF1/Promethin	Seipin partner protein, their association with Seipin is promoted by TAG	[44–47]
Pex30	MCTP2	Membrane curvature inducing reticulon homology domain containing ER protein, cooperates with Seipin in LD formation	[6,20,21,24]
Pet10	Perilipins	LD scaffolding proteins that regulate lipase activity	[52]     [53]
B. Regulators and enzymes of lipid synthesis
Pahl	Lipin	Converts PA to DAG and gets recruited to Seipin-marked ER sites to regulate LD biogenesis	[5,7,13,14,50,51]
Nem1/Spo7	CTDNEP-1/NEP1-R1	Heteromeric phosphatase complex that regulates activity of Pah1/Lipin, gets recruited to Seipin sites upon LD induction	[5,13,14]
Ice2	Serinc family members	Promotes ER membrane biogenesis by inhibiting Nem1/Spo7 phosphatase activity	[15–17]
Sct1, Gpt2	GPAT	Catalyzes acylation of glycerol-3-phosphate to lyso-PA, negatively regulated by Seipin	[10,12,48,49]
Slc1, Ale1	AGPAT	Catalyzes acylation of lyso-PA to form PA, interacts with Seipin	[10,49,50]
Dga1	DGAT	Diacylglycerol acyltransferase, catalyzes formation of TAG, colocalizes with sites of LD biogenesis	[5,10,11]
Faa1	ACSL3, FATP1	Acyl-CoA synthetases, localize to sites of LD formation	[11,54,55]