title: The HCPro from the Potyviridae family: an enviable multitasking Helper Component that every virus would like to have.
abstract: RNA viruses have very compact genomes and so provide a unique opportunity to study how evolution works to optimize the use of very limited genomic information. A widespread viral strategy to solve this issue concerning the coding space relies on the expression of proteins with multiple functions. Members of the family Potyviridae, the most abundant group of RNA viruses in plants, offer several attractive examples of viral factors which play roles in diverse infection-related pathways. The Helper Component Proteinase (HCPro) is an essential and well-characterized multitasking protein for which at least three independent functions have been described: (i) viral plant-to-plant transmission; (ii) polyprotein maturation; and (iii) RNA silencing suppression. Moreover, multitudes of host factors have been found to interact with HCPro. Intriguingly, most of these partners have not been ascribed to any of the HCPro roles during the infectious cycle, supporting the idea that this protein might play even more roles than those already established. In this comprehensive review, we attempt to summarize our current knowledge about HCPro and its already attributed and putative novel roles, and to discuss the similarities and differences regarding this factor in members of this important viral family.
authors.affiliation: Centro Nacional de Biotecnología (CNB-CSIC), Madrid, 28049, Spain.
authors.forename: Adrián A
authors.initials: AA
authors.lastname: Valli
authors.affiliation: Centro Nacional de Biotecnología (CNB-CSIC), Madrid, 28049, Spain.
authors.forename: Araiz
authors.initials: A
authors.lastname: Gallo
authors.affiliation: Centro Nacional de Biotecnología (CNB-CSIC), Madrid, 28049, Spain.
authors.forename: Bernardo
authors.initials: B
authors.lastname: Rodamilans
authors.affiliation: Center for Research in Agricultural Genomics (CRAG-CSIC-IRTA-UAB-UB), Campus UAB, Bellaterra, Barcelona, 08193, Spain.
authors.forename: Juan José
authors.identifier: 0000-0002-3176-9651
authors.initials: JJ
authors.lastname: López-Moya
authors.affiliation: Centro Nacional de Biotecnología (CNB-CSIC), Madrid, 28049, Spain.
authors.forename: Juan Antonio
authors.initials: JA
authors.lastname: García
mesh_terms: D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D010935:Plant Diseases / Q000821:virology; D017800:Potyvirus / Q000235:genetics / Q000472:pathogenicity*; D034622:RNA Interference; D012367:RNA, Viral / Q000235:genetics; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D012367:RNA, Viral; D014764:Viral Proteins; D003546:Cysteine Endopeptidases
keywords: RNA silencing suppressor; multifunctional proteins; proteinase; transmission