F-box-like domains are present in most poxvirus ankyrin repeat proteins.
Vertebrate poxviruses encode numerous proteins with the ankyrin (ANK) repeat, protein-protein interaction motif but little is known about the role(s) of this large family of poxvirus proteins. We report here that the vast majority of poxvirus ANK repeat proteins share a general molecular architecture that includes a conserved amino acid motif at the carboxyl terminus. This motif is most like the F-box seen in a range of cellular proteins. From 80-100% of the ANK repeat proteins of any one poxvirus have an F-box-like domain and we observed only one poxvirus protein with an F-box-like domain but lacking ANK repeats. The proteins of only one genus of vertebrate poxviruses lack F-box-like domains and this genus does not encode ANK repeat proteins. Many F-box proteins are recognition subunits of ubiquitin ligase complexes in which the F-box binds to core elements of the complex and protein-protein interaction domains in the remainder of the protein bind the substrate protein. These observations suggest a general model of the function of the poxvirus ANK-F-box proteins. We propose that the F-box-like domains in these proteins interact with cellular ubiquitin ligase complexes and thereby direct the ubiquitination of proteins bound to the ANK repeats. The large number of different poxviral ANK-F-box proteins suggests a wide range of cellular proteins might be subjected to ubiquitin-mediated degradation, thereby modulating diverse cellular responses to viral infection.
Mercer
Andrew A
AA
Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin, New Zealand. andy.mercer@stonebow.otago.ac.nz
Fleming
Stephen B
SB
Ueda
Norihito
N
D000595:Amino Acid Sequence; D000818:Animals; D017089:Ankyrin Repeat; D044782:F-Box Motifs / Q000502:physiology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011212:Poxviridae / Q000502:physiology*; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism; D016415:Sequence Alignment; D025801:Ubiquitin / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism; D014714:Vertebrates / Q000821:virology; D014764:Viral Proteins / Q000502:physiology
D011506:Proteins; D025801:Ubiquitin; D014764:Viral Proteins; D044767:Ubiquitin-Protein Ligases