title: Encephalomyocarditis virus Leader protein hinge domain is responsible for interactions with Ran GTPase.
abstract: Encephalomyocarditis virus (EMCV), a Cardiovirus, initiates its polyprotein with a short 67 amino acid Leader (L) sequence. The protein acts as a unique pathogenicity factor, with anti-host activities which include the triggering of nuclear pore complex hyperphosphorylation and direct binding inhibition of the active cellular transport protein, Ran GTPase. Chemical modifications and protein mutagenesis now map the Ran binding domain to the L hinge-linker region, and in particular, to amino acids 35-40. Large deletions affecting this region were shown previously to diminish Ran binding. New point mutations, especially K35Q, D37A and W40A, preserve the intact L structure, abolish Ran binding and are deficient for nucleoporin (Nup) hyperphosphorylation. Ran itself morphs through multiple configurations, but reacts most effectively with L when in the GDP format, preferably with an empty nucleotide binding pocket. Therefore, L:Ran binding, mediated by the linker-hinge, is a required step in L-induced nuclear transport inhibition.
authors.affiliation: Institute for Molecular Virology, University of Wisconsin-Madison, R.M. Bock Laboratories, 1525 Linden Dr. Madison, WI 53706, USA. bacotdavis@wisc.edu
authors.forename: Valjean R
authors.initials: VR
authors.lastname: Bacot-Davis
authors.forename: Ann C
authors.initials: AC
authors.lastname: Palmenberg
mesh_terms: D021581:Active Transport, Cell Nucleus; D019943:Amino Acid Substitution; D004686:Encephalomyocarditis virus / Q000472:pathogenicity / Q000502:physiology*; D006367:HeLa Cells; D054884:Host-Pathogen Interactions; D006801:Humans; D008958:Models, Molecular; D050505:Mutant Proteins / Q000378:metabolism; D017354:Point Mutation; D020815:Polyproteins / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D025941:Protein Interaction Mapping; D014764:Viral Proteins / Q000378:metabolism*; D020931:ran GTP-Binding Protein / Q000378:metabolism*
chemical_list: D050505:Mutant Proteins; D020815:Polyproteins; D014764:Viral Proteins; D020931:ran GTP-Binding Protein