Fermitin family homolog 3

Fermitin family homolog 3 (FERMT3) is an integrin-binding protein essential for cell adhesion in hematopoietic cells. It activates integrins β1, β2, and β3 to mediate platelet adhesion and leukocyte recruitment to endothelial cells, with isoform 2 reportedly modulating NF-κB signaling and apoptosis (UniProt: Q86UX7). FERMT3 mutations cause leukocyte adhesion deficiency 3 (LAD3), a rare immunodeficiency characterized by recurrent infections and bleeding disorders.

FERMT3 shows increased expression in post-mortem Alzheimer's disease brain tissue compared to age-matched controls, with a mean log2 fold-change of 0.90 across two subcellular fractions detected via quantitative proteomics (Chaparral AD proteomics). This upregulation suggests potential involvement in neuroinflammatory or adhesion-related pathways dysregulated in AD pathology. The biological relevance of FERMT3 elevation in AD brain—whether reflecting activated immune cell infiltration, microglia engagement, or direct neuronal contribution—requires further investigation.