Pathway · 2 proteins
Channels and ion uptake
Ion channels and dedicated uptake proteins support selective exchange.
How it works
- Potassium-channel, CorA, FeoB and TrkH annotations identify different membrane routes for ion exchange. They should not be treated as subunits of one universal channel.
- Channels provide gated conductive paths, whereas dedicated uptake proteins can use other coupling mechanisms. Ion selectivity and gating arise from the particular protein and its membrane context.
- The output is selective ion movement under suitable gradients and regulation. Net uptake, physiological direction and exact specificity need protein-specific measurements.
Grouped by the atlas’s curated pathway map. The table order is not a proven reaction order.
Its proteins
| Protein | EC | Reaction (UniProt) | Metal or cluster | Amino acids | Certainty |
|---|---|---|---|---|---|
| Ferrous iron transport protein B | — | — | Mg(2+) | 689 | System only |
| Magnesium transport protein CorA | — | Mg(2+)(in) = Mg(2+)(out) | — | 319 | System only |
Also part of this pathway
These proteins are described under another pathway, but also take part here.
| Protein | EC | Reaction (UniProt) | Metal or cluster | Amino acids | Certainty |
|---|---|---|---|---|---|
| TrkA family potassium uptake proteinHome: Potassium balance | — | — | — | 218 | System only |
| K+ transport protein homologHome: Potassium balance | — | — | — | 443 | System only |
Origins
How could magnesium and iron enter a cell before channels and transporters existed?
The books searched discuss ion channels only in present-day cells.
Magnesium is needed by every ribosome and by almost every reaction that uses ATP. CorA, a five-part channel, lets it in and closes when the cell has enough, so the cell depends on this regulated supply.
From the books: Garrett & Grisham, Biochemistry, contents p. 305 (CorA).
The wider question for this part of the cell: origins for pulling nutrients in from outside.
Sources
- Atlas pathway grouping from the VF5 reference-genome system map (Deckert et al. 1998; Braakman & Smith 2014)
Other pathways in this group: ATP-coupled transport · Ion exchange · Potassium balance · Substrate recognition · Not yet placed in a pathway