Thrombospondin

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Thrombospondins (TSP) are secreted proteins that inhibit the growth of small blood vessels ( angiogenesis ).

meaning

The thrombospondins are a family of proteins that are involved in different biological processes. For this reason, thrombospondins are called multifunctional proteins. The protein family consists of thrombospondins 1-5. A distinction is made between subgroups: Subgroup A consists of TSP1 and TSP2; subgroup B consists of TSP3, TSP4 and TSP5. TSP1 and TSP2 are homotrimers, which means that they consist of three identical subunits. TSP3, TSP4 and TSP5 are homopentamers, they consist of five identical subunits.

TSP1 was first isolated from blood platelets ( thrombocytes ) that were stimulated with thrombin . For this reason, thrombospondin was initially called a 'thrombin-sensitive protein'. TSP1 is involved in many different biological processes, such as the formation of new blood vessels ( angiogenesis ), programmed cell death ( apoptosis ), the activation of the tissue hormone TGF-β and immune regulation . TSP1 has several receptors including CD36 , CD47, and integrins .

TSP2 also inhibits angiogenesis and is involved in cell adhesion , cell migration and proliferation .

As the brain develops, TSP1 and TSP2 are made by immature astrocytes . This promotes the formation of new synapses .

Individual evidence

  1. ^ C. Daniel, K. Amann, B. Hohenstein, P. Bornstein, C. Hugo: Thrombospondin 2 Functions as an Endogenous Regulator of Angiogenesis and Inflammation in Experimental Glomerulonephritis in Mice. In: J Am Soc Nephrol . 2007 18: 788–798, doi: 10.1681 / ASN.2006080873 (free full text).
  2. ↑ Christopherson KS, Ullian EM, Stokes CC, Mullowney CE, Hell JW, Agah A, Lawler J, Mosher DF, Bornstein P, Barres BA .: Thrombospondins are astrocyte-secreted proteins that promote CNS synaptogenesis. In: Cell . 120: 421-33 (2005), doi: 10.1016 / j.cell.2004.12.020 (free full text).

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