title: Protein L-isoaspartyl methyltransferase repairs abnormal aspartyl residues accumulated in vivo in type-I collagen and restores cell migration.
abstract: Abnormal aspartyl residue formation such as L-isoaspartates occurs frequently during aging in long-lived proteins, resulting in the alteration of their structures and biological functions. In this study, we investigated the alteration of aspartyl residues in extracellular matrix (ECM) proteins, type-I collagen and fibronectin, and in integrin- and ECM-binding motifs during aging, as well as the resulting effects on cell biological functions such as migration and attachment. Using protein L-isoaspartyl methyltransferase (PIMT) to monitor the presence of L-isoaspartyl residues, we showed their accumulation during in vivo aging in type-I collagen from rats. In vitro aging of fibronectin as well as of peptides containing an integrin- or ECM-binding motif such as RGDSR, KDGEA and KDDL also resulted in the formation of L-isoaspartyl residues. While aged fibronectin does not alter cell adhesion and migration, type-I collagen aged 20 months reduced by 65% cell motility, but not adhesion, when compared to 3-month-aged type-I collagen. Finally, by repairing 20-month-old type-I collagen with recombinant PIMT (rPIMT), cell migration was recovered by 72%. These results strongly suggest that L-isoaspartyl residue formation in ECM proteins such as type-I collagen could play an important role in reducing cell migration and that PIMT could be a therapeutic tool to restore normal cell migration in pathological conditions where cell motility is crucial.
authors.affiliation: Laboratoire de Médecine Moléculaire, Université du Québec à Montréal, Québec, Canada.
authors.forename: Julie
authors.initials: J
authors.lastname: Lanthier
authors.forename: Richard R
authors.initials: RR
authors.lastname: Desrosiers
mesh_terms: D000375:Aging / Q000378:metabolism* / Q000502:physiology; D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism*; D002448:Cell Adhesion; D045744:Cell Line, Tumor; D002465:Cell Movement; D024042:Collagen Type I / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D004330:Drosophila; D005109:Extracellular Matrix / Q000737:chemistry / Q000378:metabolism; D005353:Fibronectins / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D007680:Kidney Neoplasms / Q000378:metabolism; D010455:Peptides / Q000378:metabolism; D026601:Protein D-Aspartate-L-Isoaspartate Methyltransferase / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000378:metabolism; D013379:Substrate Specificity; D013997:Time Factors
chemical_list: D024042:Collagen Type I; D005353:Fibronectins; D010455:Peptides; D011994:Recombinant Proteins; D001224:Aspartic Acid; D026601:Protein D-Aspartate-L-Isoaspartate Methyltransferase