Identification of the transmembrane dimer interface of the bovine papillomavirus E5 protein.
We have developed a genetic method to determine the active orientation of dimeric transmembrane protein helices. The bovine papillomavirus E5 protein, a 44-amino acid homodimeric protein that appears to traverse membranes as a left-handed coiled-coil, transforms fibroblasts by binding and activating the platelet-derived growth factor (PDGF) beta receptor. A heterologous dimerization domain was used to force E5 monomers to adopt all seven possible symmetric coiled-coil registries relative to one another within the dimer. Focus formation assays demonstrated that dimerization of the E5 protein is required for transformation and identified a single preferred orientation of the monomers. The essential glutamine residue at position 17 resided in the dimer interface in this active orientation. The active chimera formed complexes with the PDGF beta receptor and induced receptor tyrosine phosphorylation. We also identified E5-like structures that underwent non-productive interactions with the receptor.
Mattoon
D
D
Department of Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut CT 06510, USA.
Gupta
K
K
Doyon
J
J
Loll
P J
PJ
DiMaio
D
D
D000818:Animals; D002417:Cattle; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D003545:Cysteine / Q000235:genetics / Q000378:metabolism; D019281:Dimerization; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D009856:Oncogene Proteins, Viral / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017433:Protein Structure, Secondary; D020797:Receptor, Platelet-Derived Growth Factor beta / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors
D005656:Fungal Proteins; D009856:Oncogene Proteins, Viral; C068399:PUT3 protein, S cerevisiae; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C054304:oncogene protein E5, Bovine papillomavirus type 1; D020797:Receptor, Platelet-Derived Growth Factor beta; D003545:Cysteine