Required for aphid transmission and also has proteolytic activity. Only cleaves a Gly-Gly dipeptide at its own C-terminus. Interacts with virions and aphid stylets. Acts as a suppressor of RNA-mediated gene silencing, also known as post-transcriptional gene silencing (PTGS), a mechanism of plant viral defense that limits the accumulation of viral RNAs. May have RNA-binding activity. Has helicase activity. It may be involved in replication. Indispensable for virus replication. Indispensable for virus replication. Mediates the cap-independent, EIF4E-dependent translation of viral genomic RNAs (PubMed:31712417). Binds to the cap-binding site of host EIF4E and thus interferes with the host EIF4E-dependent mRNA export and translation (PubMed:31712417). VPg-RNA directly binds EIF4E and is a template for transcription (PubMed:31712417). Also forms trimeric complexes with EIF4E-EIF4G, which are templates for translation (PubMed:31712417). Has RNA-binding and proteolytic activities. An RNA-dependent RNA polymerase that plays an essential role in the virus replication. Involved in aphid transmission, cell-to-cell and systemis movement, encapsidation of the viral RNA and in the regulation of viral RNA amplification. a ribonucleoside 5'-triphosphate + RNA(n) = diphosphate + RNA(n+1) Hydrolyzes glutaminyl bonds, and activity is further restricted by preferences for the amino acids in P6 - P1' that vary with the species of potyvirus, e.g. Glu-Xaa-Xaa-Tyr-Xaa-Gln-|-(Ser or Gly) for the enzyme from tobacco etch virus. The natural substrate is the viral polyprotein, but other proteins and oligopeptides containing the appropriate consensus sequence are also cleaved. Hydrolyzes a Gly-|-Gly bond at its own C-terminus, commonly in the sequence -Tyr-Xaa-Val-Gly-|-Gly, in the processing of the potyviral polyprotein. Interacts with host eIF4E protein (via cap-binding region); this interaction mediates the translation of the VPg-viral RNA conjugates (PubMed:31712417). Part of a complex that comprises VPg, RNA, host EIF4E and EIF4G; this interaction mediates the translation of the VPg-viral RNA conjugates (PubMed:31712417). Interaction is possible in susceptible hosts but impaired in resistant plants: the VPg of strain LYE84 interacts with tomato eIF4E1 and eIF4E2 as well as with the Capsicum annuum eIF4E1 susceptible allele pvr2(+) but not with resistant alleles pvr2(1), pvr2(2), pvr2(3), pvr2(4), pvr2(5), pvr2(6), pvr2(7), pvr2(8) and pvr2(9), the VPg of strain SON41 interacts with C.annuum eIF4E1 susceptible alleles pvr2(+), pvr2(1), pvr2(2), pvr2(3) and pvr2(4) but not with resistant alleles pvr2(5), pvr2(6), pvr2(7), pvr2(8) and pvr2(9), the VPg of strain LYE90 interacts only with tomato eIF4E1 (PubMed:22242134, PubMed:18182024). Probably colocalizes with 6K2-induced vesicles associated with host chloroplasts. 6K-induced vesicles associate with host chloroplasts. Binds to host plant eIF4E proteins in the host nucleus. The N-terminus is involved in interaction with stylets. The central part is involved in interaction with virions and the C-terminus is involved in cell-to cell movement of the virus. VPg is uridylylated by the polymerase and is covalently attached to the 5'-end of the genomic RNA. This uridylylated form acts as a nucleotide-peptide primer for the polymerase (By similarity). Potyviral RNA is expressed as two polyproteins which undergo post-translational proteolytic processing. Genome polyprotein is processed by NIa-pro, P1 and HC-pro proteinases resulting in the production of at least ten individual proteins. P3N-PIPO polyprotein is cleaved by P1 and HC-pro proteinases resulting in the production of three individual proteins. The P1 proteinase and the HC-pro cleave only their respective C-termini autocatalytically. 6K1 is essential for proper proteolytic separation of P3 from CI (By similarity). Variant of the resistance-breaking strain SON41 has the ability to contaminate Capsicum annuum plants containing resistant alleles pvr2(+), pvr2(1), pvr2(2), pvr2(3) and pvr2(4) but not plants containing alleles pvr2(5), pvr2(6), pvr2(7), pvr2(8) and pvr2(9). Variant of the resistance-breaking strain LYE84 has the ability to contaminate Capsicum annuum plants containing the resistant allele pvr2(+) but not plants containing alleles pvr2(1), pvr2(2), pvr2(3), pvr2(4), pvr2(5), pvr2(6), pvr2(7), pvr2(8) and pvr2(9). Variant of the resistance-breaking strain SON41g has the ability to contaminate Solanum pimpinellifolium cv. LA0411 plants containing the resistant allele eIF4E1-pot1(2). Produced by conventional translation. VPg is not an intrinsically disordered protein. Belongs to the potyviridae genome polyprotein family.