CALB1 (Calbindin) is a protein of the calcium-binding protein superfamily. It functions to buffer the entry of calcium upon glutamate receptor stimulation. In the brain, it is involved in synaptic plasticity. CALB1 has high levels of expression in neurons, and it is associated with sex-specific behavioral regulation and neurobehavioral diseases. Loss of CALB1 in mice results in reduced levels of anxiety, and in humans loss of this protein has been found in patients with Huntington disease. Furthermore, downregulation of CALB1 is seen in Alzheimer’s disease (AD) and it is associated with cognitive and memory deficits in AD as well as seizure-prone neurological disorders. In immunohistochemistry, CALB1 has cytoplasmic positivity in Purkinje cells in the cerebellum, in neurons in the cerebral cortex and hippocampus, and in renal tubules. References: Endocrinology. 2016 May; 157(5): 1967–1979, PMID: 27010449; Nat Med. 2017 Nov;23(11):1377-1383, PMID: 29035369; Cell Rep. 2017 Oct 24;21(4):891-900, PMID: 29069596; Int J Neurosci. 2005 Oct;115(10):1375-82, PMID: 16162445;