TCDB is operated by the Saier Lab Bioinformatics Group
TCIDNameDomainKingdom/PhylumProtein(s)
*1.A.84.1.1









The human calcium homeostasis modulator protein 1, CALHM1 (Dreses-Werringloer et al. 2008).  The P86L polymorphism increases Abeta levels and may influence Alzheimer's disease risk by interfering with CALHM1-mediated Ca2+ permeability (Dreses-Werringloer et al. 2008). The characteristics of this channel have been reviewed studied (Ma et al. 2012) and reviewed (Ma et al. 2015). Post-translational palmitoylation controls the voltage-gating and lipid raft association (Taruno et al. 2017). CALHM1 plays a role, complementary to PANX1 (TC#1.A.25.2.1), in ATP release and downstream ciliary beat frequency modulation following a mechanical stimulus in airway epithelial cells (Workman et al. 2017). CALHM1 required for sensory perception of sweet, bitter and umami tastes. It is present in type II taste bud cells, where it plays a central role in taste perception by inducing ATP release from the cell with ATP acting as a neurotransmitter to activate afferent neural gustatory pathways. It acts both as a voltage-gated and calcium-activated ion channel mediating neuronal excitability in response to changes in extracellular Ca2+ concentration. It has poor ion selectivity and forms a wide pore (around 14 Å) that mediates permeation of Ca2+, Na+ and K+, as well as monovalent anions. It acts as an activator of the ERK1 and ERK2 cascade and triggers endoplasmic reticulum stress by reducing the calcium content of the ER (Gallego-Sandín et al. 2011). It may indirectly control amyloid precursor protein (APP) proteolysis and aggregated amyloid-beta (Abeta) peptides levels in a Ca2+ dependent manner (Dreses-Werringloer et al. 2008). The ATP comes from unusually large mitochondria that are adjacent to clusters of CALHM1 channels in the plasma membrane (Romanov et al. 2018). Thus, neurotransmission does not rely on vesicle formation.

Eukaryota
Metazoa
CALHM1 of Homo sapiens (Q8IU99)
*1.A.84.1.2









The human calcium homeostasis modulator protein 2, CALHM2

Eukaryota
Metazoa
CALHM2 of Homo sapiens (Q9HA72)
*1.A.84.1.3









The human calcium homeostasis modulator protein 3, CALHM3

Eukaryota
Metazoa
CALHM3 of Homo sapiens (Q86XJ0)
*1.A.84.1.4









Calcium homeostasis modulator 1 (CALHM1) is the pore-forming subunit of an ion channel that mediates extracellular Ca2+ regulation of neuronal excitability (Ma et al. 2015). CALHM1 (CALHM-1 or CLHM-1) is of 329 aas and exhibits 4 TMSs. 

Eukaryota
Metazoa
CALHM-1 of Caenorhabditis elegans (Q18593)
*1.A.84.1.5









FAM26D of 314aas and 4 TMSs

Eukaryota
Metazoa
FAM26D of Homo sapiens (Q5JW98)
*1.A.84.1.6









The FAM26F protein of 315 aas and probably 6 TMSs. It is probably an ion channel.  FAM26F (family with sequence similarity 26, member F) plays an important role in diverse immune responses (Malik et al. 2016).

Eukaryota
Metazoa
*1.A.84.2.1









Sea anemone CALHM homologue

Eukaryota
Metazoa
CALHM homologue of Nematostella vectensis
*1.A.84.2.2









Uncharacterized protein of 304 aas and 4 TMSs.

Eukaryota
Metazoa
UP of Nematostella vectensis (Starlet sea anemone)