The N-terminus of thrombospondin: The domain stands apart

Carrie Ann Elzie, Joanne E. Murphy-Ullrich

Research output: Contribution to journalReview articlepeer-review

62 Scopus citations

Abstract

Thrombospondin 1 (TSP1) was first recognized as a thrombin-sensitive protein associated with platelet membranes. It is secreted by numerous cell types and its expression is predominant in areas of active tissue remodeling. Thrombospondins 1 and 2 are large, trimeric, matricellular proteins, composed of multiple structural motifs which interact with a diverse array of receptors and molecules. Thrombospondin's capacity to bind multiple receptors renders it multifunctional. The functions of its isolated domains can be overlapping or contradictory. In this review, we focus on the N-terminus of the molecule, first recognized for its strong heparin binding properties and characterized by its susceptibility to proteolytic cleavage from the stalk region of thrombospondin. The N-terminus, called the heparin binding domain (HBD), interacts with a variety of macromolecules including heparan sulfate proteoglycans at the membrane and in the matrix, LDL receptor-related protein (LRP), sulfated glycolipids, calreticulin, and integrins. The HBD mediates endocytosis of thrombospondin. It functions both as a soluble and an insoluble modulator of cell adhesion and motility. In contrast to thrombospondin, the HBD has pro-angiogenic activity. We propose that the HBD of thrombospondins 1 and 2 are found primarily in the cellular microenvironment in conditions of cellular injury, stress and tissue remodeling and that the HBD conveys multiple signals involved in cellular adaptation to injury.

Original languageEnglish (US)
Pages (from-to)1090-1101
Number of pages12
JournalInternational Journal of Biochemistry and Cell Biology
Volume36
Issue number6
DOIs
StatePublished - Jun 2004

Keywords

  • Adhesion
  • Heparin binding domain
  • Migration
  • Thrombospondin

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology

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