Annexin A1

Annexin A1 (ANXA1) is a 346-amino acid calcium-binding protein that functions as a regulator of inflammatory and immune responses (UniProt: P04083). It exerts anti-inflammatory effects and modulates innate immunity through glucocorticoid-mediated pathways, while also enhancing T-cell activation and promoting differentiation toward a Th1 phenotype. The protein operates primarily by activating formyl peptide receptors, driving chemotaxis of immune cells, cytoskeletal rearrangement, and phagocytosis through calcium-dependent interactions with phospholipid membranes.

ANXA1 is broadly expressed across tissues and participates in inflammatory resolution, wound healing, and antitumor immunity via dendritic cell-mediated antigen cross-presentation. UniProt reports no specific disease associations in its curated database.

In Alzheimer's Disease, ANXA1 shows elevated expression in post-mortem AD brain compared to age-matched controls (Chaparral AD proteomics). The protein is consistently upregulated across four subcellular fractions (P2, P3, S2, S3) with a mean log2 fold-change of 1.45. This upregulation may reflect enhanced innate immune activation and neuroinflammation characteristic of AD pathology, potentially linking calcium-dependent membrane interactions and inflammatory signaling to disease progression.