Other · Connexin 43 intracellular-loop mimetic peptide
Gap19
Also known as Cx43 Gap19
A nine-residue connexin 43 loop mimetic used to distinguish hemichannel activity from established gap-junction coupling.
- Length
- 9 amino acids
- Half-life
- Not well characterised
- Mechanism
- Gap19 interferes with connexin 43 cytoplasmic loop–tail interactions involved in hemichannel gating. In characterised experimental systems it inhibits connexin 43 hemichannel activity while largely sparing established gap-junction coupling, although this distinction depends on assay conditions.
- Studied in
- Connexin-expressing cells, astrocyte cultures and animal tissue-injury models use Gap19 to investigate hemichannel currents, dye uptake and extracellular ATP release.
About Gap19
Gap19 has the sequence KQIEIKKFK and corresponds to residues 128–136 within the cytoplasmic loop of connexin 43. It was developed through mapping of interactions between the connexin intracellular loop and C-terminal tail. Unlike extracellular-loop connexin mimetics, Gap19 addresses an intracellular gating mechanism. Its short sequence is distinct from cell-penetrating fusion variants, which add further residues and should be identified separately in experimental records and analytical documentation.
Connexin hemichannels connect the cytoplasm with the extracellular space, whereas paired hemichannels form gap-junction channels between neighbouring cells. Gap19 is used to investigate this functional distinction because it can suppress connexin 43 hemichannel opening without comparably suppressing established junctional communication. Typical measurements include electrophysiological currents, dye entry and ATP release. None of these readouts is uniquely diagnostic, so parallel assessment of membrane integrity and other channel pathways remains essential.
Laboratory notes
- Distinguish unmodified Gap19 from uptake-enhanced fusion peptides; their sequence lengths and cellular access differ.
- Combine hemichannel assays with a separate gap-junction coupling assay rather than assuming selectivity from one readout.
- Control extracellular calcium, cellular stress and membrane integrity, all of which can influence dye uptake and ATP release.
Storage and reconstitution basics: storage guide.
Questions about Gap19
Is Gap19 a general gap-junction blocker?
No. It is chiefly used as a connexin 43 hemichannel-modulating probe, with established gap-junction coupling relatively preserved in characterised systems.
Does Gap19 act at an extracellular receptor?
No conventional receptor target is established. Its proposed action involves intracellular connexin 43 loop–tail interactions that influence channel gating.
Can ATP release alone confirm hemichannel inhibition?
No. ATP can leave cells through several pathways or membrane damage, so research-use studies require complementary channel and viability measurements.
Is Gap19 for human use?
No. It is supplied strictly for in-vitro laboratory research and is not for human or animal consumption.
Related research peptides
All products are sold for laboratory research use only. Not for human consumption, not a medicine, not for diagnosing, treating or preventing any condition.