Identification of sequence motifs responsible for the adhesive interaction between exon v10-containing CD44 isoforms.
Previous studies have demonstrated that CD44 isoforms containing the alternatively spliced exon v10 promote cell-cell adhesion via a mechanism that involves the recognition of chondroitin sulfate side chains presented on the surface of interacting cells in association with other CD44 molecules. Sequence analysis revealed the presence within exon v10 of two motifs that may be relevant to this interaction, a B[X(7)]B motif that may contribute to the recognition and binding of chondroitin sulfate and a serine-glycine motif that may serve as a site of chondroitin sulfate attachment. To determine whether either of these two motifs explain the unique adhesive activity of exon v10-containing CD44 isoforms, each was targeted by site-directed mutagenesis, and the adhesive activity of the resultant mutants was determined using a quantitative cell-cell binding assay. The data obtained demonstrate conclusively that it is the exon v10-encoded B[X(7)]B motif that is solely responsible for the enhanced adhesive activity of exon v10-containing CD44 isoforms.
Hayes
Gregory M
GM
Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia V6T 2B5, Canada.
Chiu
Roland
R
Carpenito
Carmine
C
Dougherty
Shona T
ST
Dougherty
Graeme J
GJ
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D019556:COS Cells; D002448:Cell Adhesion / Q000235:genetics*; D002461:Cell Line, Transformed; D002522:Chlorocebus aethiops; D005091:Exons; D006801:Humans; D018960:Hyaluronan Receptors / Q000235:genetics* / Q000502:physiology; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D016133:Polymerase Chain Reaction; D013539:Simian virus 40 / Q000235:genetics
D018960:Hyaluronan Receptors