title: The differential amino acid requirement within osteopontin in alpha4 and alpha9 integrin-mediated cell binding and migration.
abstract: Osteopontin (OPN) contains at least two major integrin recognition domains, Arg159-Gly-Asp161 (RGD) and Ser162-Val-Val-Tyr-Gly-Leu-Arg168 (SVVYGLR), recognized by alphavbeta3 and alpha5beta1 and alpha4 and alpha9 integrins, respectively. OPN is specifically cleaved by thrombin and matrix metalloproteinase (MMP)-3 or MMP-7 at a position of Arg168/Ser169 (R/S) and Gly166/Leu167 (G/L), respectively. We in this study examined the requirement of residues within SVVYGLR for the alpha4 and alpha9 integrin recognition and how MMP-cleavage influences the integrin recognition. The residues, Val164, Tyr165, and Leu167 are critical for alpha4 and alpha9 integrin recognition in both cell adhesion and cell migration. The residue Arg168 is additionally required for alpha9 integrin recognition in cell adhesion and this explains why alpha9 integrin binds to only thrombin cleaved form of OPN. alpha4 integrin is able to bind to SVVYG (MMP-cleaved form of RAA OPN-N half), while alpha9 integrin is not, supporting the above notion that Arg168 is additionally required for alpha9 integrin-mediated cell adhesion. The residue Val163 is important for alpha4, but not for alpha9 integrin recognition in cell migration. Importantly, we found that the replacement of Arg168 by Ala (R168A mutant) induces the augmentation of cell migration via alpha4 and alpha9 integrins.
authors.affiliation: Division of Molecular Immunology, Institute for Genetic Medicine, Hokkaido University, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-0815, Japan.
authors.forename: Koyu
authors.initials: K
authors.lastname: Ito
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Kon
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Nakayama
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kurotaki
authors.forename: Yoshinari
authors.initials: Y
authors.lastname: Saito
authors.forename: Masashi
authors.initials: M
authors.lastname: Kanayama
authors.forename: Chiemi
authors.initials: C
authors.lastname: Kimura
authors.forename: Hongyan
authors.initials: H
authors.lastname: Diao
authors.forename: Junko
authors.initials: J
authors.lastname: Morimoto
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Matsui
authors.forename: Toshimitsu
authors.initials: T
authors.lastname: Uede
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D002448:Cell Adhesion; D002460:Cell Line; D002465:Cell Movement; D006224:Cricetinae; D006801:Humans; D039001:Integrin alpha Chains / Q000378:metabolism*; D039441:Integrin alpha4 / Q000378:metabolism*; D019278:Matrix Metalloproteinase 3 / Q000378:metabolism; D020783:Matrix Metalloproteinase 7 / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D053495:Osteopontin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D000596:Amino Acids; D039001:Integrin alpha Chains; D010455:Peptides; D011994:Recombinant Proteins; C084613:integrin alpha9; D053495:Osteopontin; D039441:Integrin alpha4; D019278:Matrix Metalloproteinase 3; D020783:Matrix Metalloproteinase 7