Calcineurin/A0123

The serine/threonine protein phosphatase 2B catalytic subunit alpha isoform, also known as calcineurin A alpha or A0123, is a catalytic subunit of the calcium and calmodulin-dependent serine/threonine protein phosphatase 2B (PP2B).

The serine/threonine protein phosphatase 2B catalytic subunit alpha isoform, also known as calcineurin A alpha or A0123, is a catalytic subunit of the calcium and calmodulin-dependent serine/threonine protein phosphatase 2B (PP2B). This phosphatase is composed of two subunits, a regulatory component and one catalytic interactor. Calcineurin is present at high levels in the hippocampus and is enriched at synapses. Calcineurin is widely distributed, with the highest levels found in brain. Calcineurin A knock-out mice exhibit impairments in water maze learning and fear conditioning tests, however a transient reduction of calcineurin A activity facilitates long-term potentiation (LTP) in vitro and in vivo, through a protein kinase A (PKA)-dependent mechanism, improving learning and memory storage. Mutant mice with enhanced calcineurin A activity have normal short term memory but defective long-term memory.