CALHM1
calcium homeostasis modulator 1
- Ensembl:
- ENSG00000185933
- UniProt:
- Q8IU99
- OMIM:
- 612234
- Synonyms:
- FAM26C
Cilia effects upon perturbation of CALHM1
- Cilia number / % ciliated:
- Unknown
- Loss-of-function effect:
- Unknown
- Overexpression effect:
- Unknown
Phenotypes
- Mouse phenotype:
- Calhm1 knockout: muted neuronal response to low extracellular Ca2+
Subcellular localization
cilia, ciliary base, plasma membrane
Functional category
- Ion channel
- Cilium-derived extracellular vesicles
Function
Pore-forming subunit of voltage- and extracellular-Ca2+-gated ion channel; member of the large-pore channel family (related to connexins, pannexins, innexins, LRRC8/VRAC). Hexameric (CALHM1) or octameric assembly. Expressed in cortical neurons, type II taste bud cells (with CALHM3, mediating sweet/bitter/umami sensing as ATP-release channel), and other tissues. C. elegans single homolog CLHM-1 localizes to ciliary endings of sensory neurons (Tanis et al. 2013, PMID 23884934, Fig 4D), and to the periciliary membrane compartment of male tail RnB cilia where EVs are shed (Ke and Tanis 2025, bioRxiv 10.1101/2025.09.15.676301). Functional rescue between worm CLHM-1 and human CALHM1 demonstrates conservation. The P86L variant has been associated with late-onset Alzheimer's disease susceptibility, though the association remains contested.
Model organism evidence
C. elegans CLHM-1::GFP localizes to ciliary endings of sensory neurons (Tanis et al. 2013, J Neurosci, Fig 4D).
CLHM-1 localizes to the periciliary membrane compartment of male tail RnB cilia, where it is shed in extracellular vesicles. Loss of clhm-1 alters EV release dynamics (Ke & Tanis 2025).
PMIDs: 23884934, PMC12670632
Calhm1 knockout: muted neuronal response to low extracellular Ca2+. Ciliary phenotype not reported.