Taxon constraint: GO:0120020 | cholesterol transfer activity

[ValWood]

Please provide as much information as you can:

• GO term ID label:

• [x] GO:0120020 | cholesterol transfer activity

• Request to add a taxon constraint:

• • never in taxon:

never in yeast (or fungi?)

• Request to remove a taxon constraint: Please specify

• Supporting evidence if available (e.g PMID):

[ValWood]

Also

• [x] GO:0015485 | cholesterol binding |

[ValWood]

cholesterol is absent in fungi,

also (wikipedia) Cholesterol is biosynthesized by all animal cells and is an essential structural component of animal cell membranes. In vertebrates, hepatic cells typically produce the greatest amounts. In the brain astrocytes produce cholesterol and transport it to neurons.[5] It is absent among prokaryotes (bacteria and archaea), although there are some exceptions, such as Mycoplasma, which require cholesterol for growth.[6] Cholesterol also serves as a precursor for the biosynthesis of steroid hormones, bile acid[7] and vitamin D.

so I only feel comfortable adding "never in fungi" and "never in archaea"

[deustp01]

cholesterol is absent in fungi,

But does this mean that fungi confronted with exogenous cholesterol do not normally transport it? (It might - this is a question out of ignorance.)

[ValWood]

gosh, not sure. but this term

Definition	Parents

Removes cholesterol from a membrane or a monolayer lipid particle, transports it through the aqueous phase while protected in a hydrophobic pocket, and brings it to an acceptor membrane or lipid particle.

which is intracellular and act in yeast on ergosterol that is already in the membrane, I think we are probably safe to add this restriction. i.e. if there is transport of cholesterol it is probably not by an ergosterol transfer protein in the ER membrane acting on endogenous sterol.

We will probably benefit more from restriction to prevent the predictions errors (most cholesterol terms are already restricted for many years) and refine if we come across a published example. Maybe some necrotrophs do it? When I checked I could not find anything.

[ValWood]

@pgaudet reopen if you think I should revert this

[pgaudet]

This is trasnfer within the membrane. Yeast probably does that for ergosterol but not cholesterol ?

[ValWood]

It's intermembrane in this instance, PM to ER, but I agree that as far as we know these are selective for ergosterol (otherwise we would have mosaic membranes....). So for now we can keep like this.

[pgaudet]

I dont see any PR associated with this; did you add a TC?

[ValWood]

Yes, I'm sure it was in one of them.... I'm out this morning will double check when I get back

[ValWood]

I see it in here: https://github.com/geneontology/go-ontology/edit/master/src/taxon_constraints/never_in_taxon.tsv

[pgaudet]

Perfect, thanks

Please if yo u can link pull requests to the appropriate ticket it's easier to follow up on what was done/not done.