NTR: protein-mitochondrial outer membrane tethering activity

[ValWood]

Please provide as much information as you can:

• Suggested term label:

~NTR: mitochondrion-hibernating ribosome tether activity~

NTR mitochondrial outer membrane tethering activity --mitochondrion-mitochondrion outer membrane tether activity --mitochondrion-plasma membrane adaptor activity

• Definition (free text)

The binding activity of a molecule that brings together a hibernating cytosolic ribosome with the mitochondrial outer membrane, to establish or maintain the localization of the hibernating ribosome.

• Reference, in format PMID:#######

PMID:39379376 Title | Ribosomes hibernate on mitochondria during cellular stress. https://europepmc.org/article/MED/39379376#free-full-text pretty electron tomography

• Gene product name and ID to be annotated to this term

https://www.pombase.org/gene/SPAC6B12.15

• Parent term(s)

GO:0043495 | protein-membrane adaptor activity

• Children terms (if applicable) Should any existing terms that should be moved underneath this new proposed term?

• Any other information

We then used in situ cryo-ET to assess whether ribo- somal tethering to mitochondria was affected in the Δcpc2 strain. The tomograms showed fragmented circular mitochondria, as observed in WT cells, while no ribosome tethering was observed after 7 days of cells growing at low glucose concentrations (Fig. 5c, d, Supplementary Fig. 10 and Supplementary Movie 3). Therefore, our data reveals a distinct mode of interaction between ribosomes and mitochondria, which is disrupted by the deletion of Cpc2. Our results indicate that Cpc2 is implicated in both cell viability and ribosome tethering to mitochondria under glucose depletion conditions, emphasizing its key role in mitochondrial homeostasis.

[ValWood]

I have cpc2 (RAC K1) annotated as "ribosome binding"

but RACK1 is sometimes described as a "ribosome receptor" due to its dual role: it serves both as a core ribosomal component and as a scaffold for recruiting other signaling proteins to the ribosome. The term "receptor" in this context emphasizes RACK1's function in docking signaling molecules (like kinases) onto the ribosome, enabling signal transduction pathways to directly influence translation.

So, I guess the ribosome binding annotations. should be removed.

Also, consider a general parent of

mitochondrion outer membrane-hibernating ribosome tether activity

ribosome adaptor exact synonym ribosome receptor (since this is using that functionality to attach to the mitochondrion?)

[ValWood]

I guess for this I can use GO:0043495 | protein-membrane adaptor activity but I would have no way to specify the mitochondrial outer membrane? and it isn't an individual protein

[hattrill]

If we made the term: 'protein-outer mitochondrial membrane adaptor activity' this could be applied to a number of proteins (There is one that tethers active ribosomes that I've come across, but can't think of it just now).

[pgaudet]

Good point, we dont have an activity that describes a single gene product.