Thrombospondin-4 (TSP4) is a member of the extracellular calcium-binding protein family and is involved in cell adhesion and migration. It acts as an extracellular mitogen and stimulates early erythroid progenitor's proliferation in the presence of EPO. It is an adhesive glycoprotein that mediates cell-to-cell and cell-to-matrix interactions. Can bind to fibrinogen, fibronectin, laminin, and type V collagen. In the brain, TSP4 has been implicated in neurite growth and can elicit synapse formation. It shows significantly higher expression levels in the human adult cortex than in other primates and this change has been hypothesized to have played a role in humans having increased synaptic density and increased rates of neurite growth. It also has been shown to accumulate in amyloid plaques and perhaps increase human susceptibility to developing Alzheimer’s disease.
Swiss-Prot Accession Number: P35443