Fig. 1. The TSP1 receptor CD47.

A model for the interaction of TSP1 with the heparan sulfate modified isoform of CD47 is presented. Modification of CD47 at Ser⁶⁴ is required for inhibitory TSP1 signaling in T cells (Kaur et al., 2011). A long range disulfide bond links the extracellular IgV domain (blue) to the extracellular loop between the transmembrane segments TM4 and TM5 and is required for CD47 signaling (Rebres et al., 2001). BLINK Blast analysis of human CD47 identified multiple presenilins that show significant homology with its transmembrane domain. The lower panel shows alignment of transmembrane domains of xenopus and human presenilin-1 with those of human and mouse CD47. CD47 and presenilin-1 sequences were aligned using the Segment Pair Overlap algorithm of MACAW. Capital letters indicate aligned blocks, and shading indicates conserved residues.