Sheep Anti-Human Vimentin polyclonal antibody for IEP, ELISA. Intermediate filaments (IFs), along with microfilaments and microtubules, are the three major filament systems that form the architectural basis of most eukaryotic cells. Vimentin, with a molecular weight of 58 kDa, is a Type III intermediate filament found in cells of mesenchymal origin including endothelial cells, megakaryocytes and platelets as well as in most cultured cell lines. As with other IFs, vimentin provides a physical linkage between the plasma membrane and the nuclear envelope. The carboxy-terminus of vimentin associates with the lamin B of the nuclear envelope whereas the amino-terminus associates with the plasma membrane either directly or indirectly. In general, it is believed that IFs, including vimentin, provide a network onto which various enzyme systems, intracellular structures and organelles are spatially arranged within the cytoplasm. IFs may also play an active role in the re-organization of intracellular components in response to extracellular signals via their disassembly and reassembly. In normal vascular endothelium, vimentin, along with other cytoskeletal proteins, are typically not exposed to extracellular plasma proteins. However, with damage to endothelial cells, exposure of these cytoskeletal components may play a role in thrombogenesis or inflammatory responses. For example, it has been demonstrated that vimentin can bind complement components as wells as immunoglobulins. Vimetin has also been shown to bind vitronectin and vitronectin/PAI-1 complexes in LPS-damaged endothelial cells.