Podoplanin belongs to the podoplanin family, also known as Glycoprotein 38. Podoplanin is synthesized as a 172 amino acid (aa) precursor with a 22 aa signal sequence, a 119 aa extracellular domain (ECD), a 21 aa transmembrane region, and a short, 10 aa cytoplasmic tail. Detected at high levels in lung and brain, at lower levels in kidney, stomach, liver, spleen and esophagus, and not detected in skin and small intestine. Expressed in epithelial cells of choroid plexus, ependyma, glomerulus and alveolus, in mesothelial cells and in endothelia of lymphatic vessels. Also expressed in stromal cells of peripheral lymphoid tissue and thymic epithelial cells. Detected in carcinoma cell lines and cultured fibroblasts. Expressed at higher levels in colon carcinomas than in normal colon tissue. It can interacts with CLEC1B; the interaction is independent of CLEC1B glycosylation and activates CLEC1B. It may be involved in cell migration and/or actin cytoskeleton organization. When expressed in keratinocytes, induces changes in cell morphology with transfected cells showing an elongated shape, numerous membrane protrusions, major reorganization of the actin cytoskeleton, increased motility and decreased cell adhesion. Required for normal lung cell proliferation and alveolus formation at birth. Ligand for CLEC1B, a platelet receptor. Induces platelet aggregation. Does not have any effect on folic acid or amino acid transport. Does not function as a water channel or as a regulator of aquaporin-type water channels.