Gap junction protein gamma-3 (GJC3)

Gap junction protein gamma-3 (GJC3), also known as Connexin-29 (Cx29), is a member of the connexin family of gap junction proteins that aggregate to form hexameric hemichannels (connexons) in the plasma membrane[1][2][3]. These channels dock to connexons in adjacent cells, creating gap junctions that allow direct cytoplasmic exchange of ions and small molecules (≤1 kDa), critical for intercellular communication and coordination in many tissues[1][8]. Unlike some connexins, Cx29 is highly expressed in myelin-forming glial cells of the central and peripheral nervous systems and colocalizes with Kv1.2 potassium channels, suggesting a role in ion handling during saltatory conduction[2]. GJC3 mutations are associated with disorders such as nonsyndromic hearing loss and Charcot-Marie-Tooth disease (type X)[1][2]. Structural studies show GJC3 forms selective chloride ion channels[3]. No specific drugs are currently known to target GJC3, but the broader connexin family is a subject of therapeutic interest in neurology and hearing disorders. Key context: - Gene identifiers: HGNC:17495, NCBI Gene: 349149, UniProt: Q8NFK1[1]. - Structure: Four transmembrane domains, two extracellular loops, cytoplasmic N- and C-terminals[8]. - Expression: CNS, PNS, inner ear, concentrated in myelin sheaths[2][5]. - Disease relevance: Mutations lead to impaired neuronal communication or dysmyelination; R15G mutation is notable for hearing loss[3]. - Mechanisms of action and drugs: No approved drugs; in principle, small molecules, peptides, or antisense oligonucleotides that modify gap junction conductance could affect function, but such agents are not documented for GJC3 specifically. - Safety concerns: Disrupted gap junction function can impede electrical/chemical signaling in nerves or other tissues, causing adverse neurological or developmental effects.

Other names

Connexin-29Cx29Connexin-30.2Cx30.2Connexin-31.3Cx31.3GJE1Gap junction epsilon-1 proteingap junction gamma-3 protein

Channel modulation (generic for connexin family: block or enhance channel permeability), No specific drug mechanism described for GJC3