title: Juxtanodin is an intrinsically disordered F-actin-binding protein.
abstract: Juxtanodin, also called ermin, is an F-actin-binding protein expressed by oligodendrocytes, the myelin-forming cells of the central nervous system. While juxtanodin carries a short conserved F-actin-binding segment at its C terminus, it otherwise shares no similarity with known protein sequences. We carried out a structural characterization of recombinant juxtanodin in solution. Juxtanodin turned out to be intrinsically disordered, as evidenced by conventional and synchrotron radiation CD spectroscopy. Small-angle X-ray scattering indicated that juxtanodin is a monomeric, highly elongated, unfolded molecule. Ensemble optimization analysis of the data suggested also the presence of more compact forms of juxtanodin. The C terminus was a strict requirement for co-sedimentation of juxtanodin with microfilaments, but juxtanodin had only mild effects on actin polymerization. The disordered nature of juxtanodin may predict functions as a protein interaction hub, although F-actin is its only currently known binding partner.
authors.affiliation: Department of Biochemistry, University of Oulu, Oulu, Finland.
authors.forename: Salla
authors.initials: S
authors.lastname: Ruskamo
authors.forename: Maryna
authors.initials: M
authors.lastname: Chukhlieb
authors.forename: Juha
authors.initials: J
authors.lastname: Vahokoski
authors.forename: Saligram Prabhakar
authors.initials: SP
authors.lastname: Bhargav
authors.forename: Fengyi
authors.initials: F
authors.lastname: Liang
authors.forename: Inari
authors.initials: I
authors.lastname: Kursula
authors.forename: Petri
authors.initials: P
authors.lastname: Kursula
mesh_terms: D000199:Actins / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D000465:Algorithms; D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism; D002942:Circular Dichroism; D008840:Microfilament Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000378:metabolism; D011485:Protein Binding; D017433:Protein Structure, Secondary; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry* / Q000378:metabolism; D053838:Scattering, Small Angle; D017386:Sequence Homology, Amino Acid; D012984:Software; D012996:Solutions / Q000737:chemistry; D013552:Swine; D014961:X-Ray Diffraction
chemical_list: D000199:Actins; D002352:Carrier Proteins; C505830:Ermn protein, rat; C034037:F-actin-binding proteins; D008840:Microfilament Proteins; D011994:Recombinant Proteins; D012996:Solutions