Isoform 3 of Sarcoplasmic/endoplasmic reticulum calcium ATPase 2

Isoform 3 of sarcoplasmic/endoplasmic reticulum calcium ATPase 2 (SERCA2), encoded by ATP2A2, is a calcium pump that regulates intracellular calcium homeostasis by transporting Ca²⁺ from the cytoplasm into the endoplasmic reticulum lumen (UniProt: P16615-3). This protein is essential for maintaining ER calcium stores and plays a critical role in muscle and cardiac function, as well as calcium signaling in non-muscle tissues.

SERCA2 is widely expressed across tissues including heart, skeletal muscle, and brain, where it modulates calcium-dependent processes including synaptic transmission and cellular excitability. The UniProt record contains no curated disease associations in its standardized annotations.

This isoform shows reduced abundance in Alzheimer's disease brain tissue. Chaparral AD proteomics analysis of post-mortem AD brain versus age-matched controls (TMT-labeled, 4 subcellular fractions) detected SERCA2 isoform 3 as downregulated with a mean log2 fold-change of −0.84, suggesting impaired calcium pump capacity in AD pathology (Chaparral AD proteomics).