Reactome: A Curated Pathway Database

CALB1 binds 4xCa2+

Stable Identifier
Homo sapiens
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Calbindin (CALB1, aka D-28K, CAB27) is a calcium binding protein with six EF hand domains, functions as both a calcium buffer and a sensor protein and plays a vital role in neurological function. CALB1 binds four calcium ions at its four functional calcium-binding sites (EF hands 1,3,4 and 5), subsequently undergoing a conformational change. EF hands 2 and 6 are known not to bind calcium (Kojetin et al. 2006, Hobbs et al. 2009). Cholinergic neurons of the basal forebrain (BFCN) are selectively vulnerable in Alzheimer's disease (AD). Most of the BFCN in the human brain contain CALB1 and a large proportion lose their CALB1 in the course of normal aging. The BFCN which degenerate in AD lack CALB1, depriving neurons of the capacity to buffer high levels of intracellular calcium and thus leaving them vulnerable to pathological processes, such as those in AD, which can cause increased intracellular calcium, leading to their degeneration (Geula et al. 2003, Ahmadian et al. 2015).

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