Plays a central role in cell adhesion in hematopoietic cells (By similarity). Acts by activating the integrin beta-1-3 (ITGB1, ITGB2 and ITGB3) (PubMed:18278053). Required for integrin-mediated platelet adhesion and leukocyte adhesion to endothelial cells (PubMed:19234461). Required for activation of integrin beta-2 (ITGB2) in polymorphonuclear granulocytes (PMNs) (PubMed:18278053). Interacts with ITGB1, ITGB2 and ITGB3 (via cytoplasmic tails). Present in the F-actin surrounding ring structure of podosomes, which are specialized adhesion structures of hematopoietic cells. Specifically expressed in hematopoietic cells. The FERM domain is not correctly detected by PROSITE or Pfam techniques because it contains the insertion of a PH domain. Mice suffer from fatal anemia, caused by severe bleeding and erythrocytopenia. Mice also show markedly reduced size and cellularity. Platelets cannot activate integrins despite normal Talin (Tln1) expression. Belongs to the kindlin family.