The octapeptide RFYVVMWK constitutes the active sequence within the 30-mer peptide named C₄ as it is essential for the cell attachment activity of the TS1 CBD. It supports the attachment of G361 melanoma cells and inhibits their adhesion to the rec CBD of TS1. Moreover, this peptide appears to be highly conserved in all TS1 isoforms, and a related sequence is also present in the fragment F9 of laminin. 4N1 has been used as CD47 agonist.