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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.

Accession Number:Q8IU99
Protein Name:Calcium homeostasis modulator protein 1
Length:346
Molecular Weight:38264.00
Species:Homo sapiens (Human) [9606]
Number of TMSs:5
Location1 / Topology2 / Orientation3: Cell membrane1 / Multi-pass membrane protein2
Substrate Ca2+

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FASTA formatted sequence
1:	MMDKFRMIFQ FLQSNQESFM NGICGIMALA SAQMYSAFDF NCPCLPGYNA AYSAGILLAP 
61:	PLVLFLLGLV MNNNVSMLAE EWKRPLGRRA KDPAVLRYMF CSMAQRALIA PVVWVAVTLL 
121:	DGKCFLCAFC TAVPVSALGN GSLAPGLPAP ELARLLARVP CPEIYDGDWL LAREVAVRYL 
181:	RCISQALGWS FVLLTTLLAF VVRSVRPCFT QAAFLKSKYW SHYIDIERKL FDETCTEHAK 
241:	AFAKVCIQQF FEAMNHDLEL GHTHGTLATA PASAAAPTTP DGAEEEREKL RGITDQGTMN 
301:	RLLTSWHKCK PPLRLGQEEP PLMGNGWAGG GPRPPRKEVA TYFSKV