Annexin A2

Annexin A2 (ANXA2) is a calcium-regulated membrane-binding protein that binds two calcium ions with high affinity in the presence of anionic phospholipids (UniProt: P07355). The protein participates in multiple cellular processes including endosomal membrane stabilization, lipid metabolism regulation through PCSK9 inhibition, and endothelial fibrinolytic function. It also serves as a receptor for pathogenic toxins from microbial infection.

ANXA2 is broadly expressed and functions across multiple tissue and cellular compartments, particularly in membrane trafficking and lipid-dependent signaling pathways. UniProt records no specific disease associations in its curated data; however, the protein has been detected in inflammatory and metabolic contexts relevant to endothelial and innate immune function.

Annexin A2 shows increased abundance in Alzheimer's Disease brain tissue. In post-mortem AD brain compared to age-matched controls across multiple subcellular fractions, ANXA2 was significantly upregulated with a mean log2 fold-change of 1.36 (Chaparral AD proteomics). This elevation across multiple fractions suggests a consistent AD-associated increase, potentially reflecting altered calcium signaling, membrane dynamics, or inflammatory responses in the diseased brain.