ERG28 (YER044C, P40030) review notes

Identity

• Ergosterol biosynthetic protein 28, alias BUD18; ERG28 family; multi-pass ER membrane protein [UniProt:P40030].
• Conserved from yeast to plants and humans PMID:11160377.

Function: non-catalytic scaffold of the C-4 demethylation complex

• Identified by expression-profile compendium as a sterol gene PMID:10929718.
• Deletion: slow growth, not ergosterol auxotroph, C-4 demethylation lesion PMID:11160377; accumulation of 3-keto and carboxylic acid sterols PMID:11160377.
• ER localisation and complex with Erg25/26/27 PMID:12119386; scaffold model PMID:12119386.
• Bridges to Erg6 PMID:15522820; Erg6 ER level halves in erg28 PMID:15522820.
• Split-ubiquitin: Erg28 with Erg11/Erg25/Erg27 forms core of "ergosome" PMID:16300994; also Erg1, Erg11 PMID:15995173.
• Conserved motif needed for C-4 demethylation PMID:29319811.
• PDR10 interaction (PMID:23831759) is a high-throughput MYTH screen hit of an ABC transporter; ERG28 not discussed in the text; no functional significance.

Curation conclusions

• Core MF: GO:0030674 protein-macromolecule adaptor activity (scaffold); BP GO:0006696 ergosterol biosynthetic process; CC GO:0005789 ER membrane.
• No catalytic activity. protein binding IPIs with Erg25/26/27 are captured better by the adaptor term.
• YeastCyc does not list ERG28 in PWY3O-31704; the module adds it as scaffold.