Calcium Homeostasis Modulator 1 (CALHM1)

CALHM1 encodes a calcium channel that plays a role in processing of amyloid-beta precursor protein. A polymorphism at this locus has been reported to be associated with susceptibility to late-onset Alzheimer's disease in some populations, but the pathogenicity of this polymorphism is unclear. The deduced 346-amino acid CALHM1 protein contains a hydrophobic loop that does not cross the membrane, 3 transmembrane segments, and 2 putative N-glycosylation sites. RT-PCR detected highest CALHM1 expression in whole adult brain, spinal cord, and all adult brain regions examined, with much lower expression in all other tissues examined, including fetal brain. Immunohistochemical analysis revealed that CALHM1 localized to the endoplasmic reticulum (ER) and plasma membrane in transfected cells.