[The family of calsyntenins: learning and memory related genes].

Calsyntenins (Cst) comprise a family of transmembrane proteins with the unique potential to link extracellular proteolytic activity with intracellular Ca2+ signaling. It is a molecular class of calcium binding protein, which can bind calcium ion and being involved in signal transduction and cell communication. It contains three members, calsyntenin-1, calsyntenin-2 and calsyntenin-3, which are postsynaptic membrane proteins and predominantly expressed in brain neurons. Each of the three calsyntenins exhibits a distinct neuronal mRNA expression pattern. The three calsyntenins exhibit the highest degree of structural diversity. The calsyntenin-1 is located in the postsynaptic membrane of CNS synapses and a proteolytically processed protein of the postsynaptic membrane with a calcium-binding cytoplasmic domain. Calsyntenin-1 is a dynamic modulator of postsynaptic calcium by extracellular proteolysis. Calsyntenin-1 may modulate Ca2+ transients locally either beneath the postsynaptic membrane or around intracellular Ca2+ stores, such as LTP and LTD. Recent studies showed that impairment of the coordinated metabolic regulation of APP and calsyntenins and the consequent loss of the reciprocal regulation by APP and calsyntenins in the gene transactivation could lead to neural disorders and disease progression in AD. This is important to disclose the mechanism of AD and develop new drugs for treating AD.