HcPro, a multifunctional protein encoded by a plant RNA virus, targets the 20S proteasome and affects its enzymic activities.
The proteasome is a multicatalytic complex involved in many cellular processes in eukaryotes, such as protein and RNA turnover, cell division, signal transduction, transcription and translation. Intracellular pathogens are targets of its enzymic activities, and a number of animal viruses are known to interfere with these activities. The first evidence that a plant virus protein, the helper component-proteinase (HcPro) of Lettuce mosaic virus (LMV; genus Potyvirus), interferes with the 20S proteasome ribonuclease is reported here. LMV infection caused an aggregation of the 20S proteasome to high-molecular mass structures in vivo, and specific binding of HcPro to the proteasome was confirmed in vitro using two different approaches. HcPro inhibited the 20S endonuclease activity in vitro, while its proteolytic activities were unchanged or slightly stimulated. This ability of HcPro, a pathogenicity regulator of potyviruses, to interfere with some of the catalytic functions of the 20S proteasome suggests the existence of a novel type of defence and counter-defence interplay in the course of interaction between potyviruses and their hosts.
Ballut
Lionel
L
UMR 1095 ASP (INRA-Université Blaise Pascal), Campus des Cézeaux, 24 Avenue des Landais, 63177 Aubière Cedex, France.
Drucker
Martin
M
UMR 385 BGPI, CIRAD-INRA-ENSAM, TA 41/K, Campus de Baillarguet, 34398 Montpellier Cedex 5, France.
Pugnière
Martine
M
CPBS, CNRS UMR 5160, Faculté de Pharmacie, 15 Av. Charles Flahault, 34093 Montpellier Cedex 5, France.
Cambon
Florence
F
UMR 1095 ASP (INRA-Université Blaise Pascal), Campus des Cézeaux, 24 Avenue des Landais, 63177 Aubière Cedex, France.
Blanc
Stéphane
S
UMR 385 BGPI, CIRAD-INRA-ENSAM, TA 41/K, Campus de Baillarguet, 34398 Montpellier Cedex 5, France.
Roquet
Françoise
F
CPBS, CNRS UMR 5160, Faculté de Pharmacie, 15 Av. Charles Flahault, 34093 Montpellier Cedex 5, France.
Candresse
Thierry
T
UMR GDPP (INRA-UVSB2), IBVM, BP 81, 33883 Villenave d'Ornon Cedex, France.
Schmid
Hans-Peter
HP
UMR 1095 ASP (INRA-Université Blaise Pascal), Campus des Cézeaux, 24 Avenue des Landais, 63177 Aubière Cedex, France.
Nicolas
Paul
P
UMR 1095 ASP (INRA-Université Blaise Pascal), Campus des Cézeaux, 24 Avenue des Landais, 63177 Aubière Cedex, France.
Gall
Olivier Le
OL
UMR GDPP (INRA-UVSB2), IBVM, BP 81, 33883 Villenave d'Ornon Cedex, France.
Badaoui
Saloua
S
UMR 1095 ASP (INRA-Université Blaise Pascal), Campus des Cézeaux, 24 Avenue des Landais, 63177 Aubière Cedex, France.
D002846:Chromatography, Affinity; D002847:Chromatography, Agarose; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D018545:Lactuca / Q000821:virology*; D010447:Peptide Hydrolases / Q000378:metabolism; D017800:Potyvirus / Q000235:genetics / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D011485:Protein Binding; D012328:RNA Viruses / Q000235:genetics / Q000378:metabolism; D012367:RNA, Viral / Q000378:metabolism; D012260:Ribonucleases / Q000378:metabolism; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
D012367:RNA, Viral; D014764:Viral Proteins; D012260:Ribonucleases; D010447:Peptide Hydrolases; D003546:Cysteine Endopeptidases; C072775:HC-Pro protein, potyvirus; D046988:Proteasome Endopeptidase Complex