Podoplanin is a transmembrane glycoprotein that is expressed in various human tissues, such as renal podocytes (podoplanin is named after these structural elements) and fibroblastic reticular cells (FRCs) of the lymph node. Podoplanin is strongly expressed on lymphatic endothelial cells, but not on blood endothelial cells. Therefore, it is considered a good marker for lymphatic vessels. Podoplanin binds to the human platelet receptor CLEC-2 and leads to platelet activation.
The exact physiological function of podoplanin is unknown - it is assumed that it is involved in developmental processes of the lung and lymphatic vascular system.
Podoplanin is considered to be expressed in lymphatic endothelia, lymphangiomas, hemangiodotheliomas, Kaposi's sarcoma and angiosarcoma.