FIGURE 2: Model of LD biogenesis from specialized ER subdomains. a) Fld1 and Nem1 show punctate ER distribution in yeast mutants lacking LDs. b) Nem1 gets activated at sites where Fld1 and Nem1 colocalize (Fld1/Nem1 sites). c) Activation of Pah1 and production of DAG at these sites. DAG enrichment drives Yft2 recruitment at Fld1/Nem1 sites. d) Pex30 localizes to Fld1/Nem1/Yft2-containing ER subdomains, and deforms the ER bilayer. e-g) Sites containing Fld1/Nem1/Yft2/Pex30 become functional in recruiting TAG producing enzymes: Lro1 and Dga1 are recruited (e), resulting in neutral lipid synthesis (f), and formation of neutral lipid lenses (g). h, i) Lenses grow into nascent LDs that are recognized by bona fide LD marker proteins, such as Pet10 and Erg6, facilitating nascent LDs to emerge towards the cytoplasm (h) where they further grow in size and mature (i). Mature LDs acquire additional LD surface proteins and remain connected to the ER to promote bidirectional transport of proteins and lipids between the two compartments. This figure has been modified from Choudhary et al (2020). J Cell Biol; doi: 10.1083/jcb.201910177