Intracellular factor XIII: cellular distribution of factor XIII subunit a in humans.

In addition to the plasma where factor XIII subunit A is present as part of the heterodimers of the tetrameric fibrin-stabilizing factor, homodimers of factor XIII A can also be detected in cellular localization in different human tissues. Experimental findings verified that these cells belong to the megakaryocyte/ platelet and the monocyte/macrophage cell lines. Additionally, factor XIII A is present in hepatocytes localized mainly around central veins in the liver and occasionally expressed in certain malignantly transformed cells. It is reasonable to suppose that factor XIII A acts not only as a member of the clotting cascade, but also as a cellular enzyme that can catalyze molecular interactions intracellularly (during the assembly/reassembly of the cytoskeleton) or extracellularly (in the connective tissue matrix around the cells containing it).