Plasma membrane calcium-transporting ATPase (PMCA) (PMCA)

The Plasma membrane calcium-transporting ATPase (PMCA) is a critical P-type ATPase responsible for maintaining low resting levels of cytosolic calcium by pumping Ca2+ ions out of the cell (UniProt, 2023). It operates with high affinity for calcium but low capacity, making it essential for the fine-tuning of intracellular calcium signaling rather than bulk removal (PubMed: 23831534). There are four main isoforms (PMCA1-4) encoded by the ATP2B1-4 genes, with PMCA1 and 4 being ubiquitously expressed while PMCA2 and 3 are more tissue-specific, particularly in the nervous system and ears (PubMed: 22522152). Dysregulation of PMCA is linked to various pathologies, including hypertension (ATP2B1), sensorineural hearing loss (ATP2B2), and neurodegenerative disorders (PubMed: 21258341, PubMed: 9618164). While PMCA is a significant therapeutic target for modulating calcium signaling, its ubiquitous nature presents challenges for drug specificity and safety (PubMed: 11566461). Current pharmacological research focuses on isoform-specific modulators to treat conditions like cardiovascular disease and cancer (PubMed: 26461347). The pump's activity is regulated by calmodulin, which increases its affinity for calcium and its maximum pumping rate (StatPearls, 2023). In addition to its role in homeostasis, PMCA4 has been specifically identified as a key regulator of nitric oxide signaling in the heart and sperm motility (PubMed: 15103337).

Other names

Plasma membrane Ca2+-ATPaseCalcium pumpATP2BPlasma membrane calcium pumpCalcium-transporting ATPase

The PMCA pump functions by coupling the hydrolysis of one ATP molecule to the expulsion of one calcium ion from the cytosol to the extracellular space, typically in exchange for protons, to maintain low intracellular calcium levels (PubMed: 23831534).