TMEM38B
Identifiers
Aliases	TMEM38B, C9orf87, D4Ertd89e, OI14, TRIC-B, TRICB, bA219P18.1, transmembrane protein 38B
External IDs	OMIM: 611236; MGI: 1098718; HomoloGene: 10010; GeneCards: TMEM38B; OMA:TMEM38B - orthologs
Gene location (Mouse) Chr. Chromosome 4 (mouse)[1] Band 4 B2|4 28.76 cM Start 53,826,045 bp[1] End 53,862,019 bp[1]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in Top expressed in More reference expression data BioGPS n/a
Gene ontology Molecular function Cellular component Biological process Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 55151 52076 Ensembl n/a ENSMUSG00000028420 UniProt Q9NVV0 Q9DAV9 RefSeq (mRNA) NM_018112 NM_028053 RefSeq (protein) NP_060582 NP_082329 Location (UCSC) n/a Chr 4: 53.83 – 53.86 Mb PubMed search [2] [3]
Wikidata
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Trimeric intracellular cation-selective channel B (TRIC-B) is a monovalent cation channel in the ER membrane encoded by the transmembrane protein 38B (TMEM38B) gene.^[4][5] It is one of two known TRIC proteins, the other being TRIC-A.

TRIC-B is permeable to both Na⁺ and K⁺ but not divalent cations like Ca²⁺.^[4] The channel exhibits marked voltage-dependence, becoming more open when the cytosol is more positively charged than the ER lumen. There at least four major sub-conductance states (with 80%, 60%, 46% and 30% of the conductance of the fully-opened channel).^[4] TMEM38B-knockout mice exhibit reduced IP₃-receptor-mediated Ca²⁺ release.^[4] As such, K⁺ flux into the ER through TRIC-B is thought to support IP₃-induced efflux of Ca²⁺ ions through IP₃-gated Ca²⁺ channels in the ER membrane.

Null mutations in TMEM38B reduce the levels of functional TRIC-B in heterozygotes and abolish expression of functional TRIC-B in homozygotes. Such mutations are an uncommon but relatively severe cause of autosomal recessive osteogenesis imperfecta or "brittle bone disease".^[5]

• TMEM38A
• Trimeric intracellular cation-selective channel