The bovine papillomavirus type 4 E8 protein binds to ductin and causes loss of gap junctional intercellular communication in primary fibroblasts.
The E8 open reading frame of bovine papillomavirus type 4 encodes a small hydrophobic polypeptide which contributes to cell transformation by conferring anchorage-independent growth. Using an in vitro translation system, we show that the E8 polypeptide binds to ductin, the 16-kDa proteolipid that forms transmembrane channels in both gap junctions and vacuolar H+-ATPase. This association is not due to nonspecific hydrophobic interactions. PPA1, a Saccharomyces cerevisiae polypeptide homologous (with 25% identity) to ductin, does not complex with E8. Furthermore, E5B, structurally similar to E8 but with no transforming activity, does not form a complex with ductin. Primary bovine fibroblasts expressing E8 show a loss of gap junctional intercellular communication, and it is suggested that this results from the interaction between E8 and ductin.
Faccini
A M
AM
Beatson Laboratories, Beatson Institute for Cancer Research, Bearsden, Glasgow, United Kingdom.
Cairney
M
M
Ashrafi
G H
GH
Finbow
M E
ME
Campo
M S
MS
Pitts
J D
JD
D000818:Animals; D052688:Bovine papillomavirus 1 / Q000235:genetics / Q000378:metabolism*; D002417:Cattle; D002450:Cell Communication; D015536:Down-Regulation; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism*; D017629:Gap Junctions; D015870:Gene Expression; D009856:Oncogene Proteins, Viral / Q000235:genetics / Q000378:metabolism*; D011510:Proteolipids / Q000378:metabolism*; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D025262:Vacuolar Proton-Translocating ATPases
D009856:Oncogene Proteins, Viral; D011510:Proteolipids; C082471:ductin; C054304:oncogene protein E5, Bovine papillomavirus type 1; D025262:Vacuolar Proton-Translocating ATPases; D006180:Proton-Translocating ATPases