The function of FERMT3 (FERM domain containing kindlin 3, ENSG00000149781) is as follows. Plays a central role in cell adhesion in hematopoietic cells (PubMed:19234463, PubMed:26359933). Acts by activating the integrin beta-1-3 (ITGB1, ITGB2 and ITGB3) (By similarity). Required for integrin-mediated platelet adhesion and leukocyte adhesion to endothelial cells (PubMed:19234460). Required for activation of integrin beta-2 (ITGB2) in polymorphonuclear granulocytes (PMNs) (By similarity). {ECO:0000250|UniProtKB:Q8K1B8, ECO:0000269|PubMed:19234460, ECO:0000269|PubMed:19234463, ECO:0000269|PubMed:26359933}. Isoform 2 may act as a repressor of NF-kappa-B and apoptosis. {ECO:0000269|PubMed:19064721, ECO:0000269|PubMed:19234460, ECO:0000269|PubMed:19234463}.