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 (By similarity). Binds to the cap-binding site of host EIF4E and thus interferes with the host EIF4E-dependent mRNA export and translation (By similarity). VPg-RNA directly binds EIF4E and is a template for transcription (By similarity). Also forms trimeric complexes with EIF4E-EIF4G, which are templates for translation (By similarity). 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. Binds 1 Fe(2+) ion per subunit. Probably colocalizes with 6K2-induced vesicles associated with host chloroplasts. 6K-induced vesicles associate with host chloroplasts. 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). Genome polyprotein of potyviruses undergoes post-translational proteolytic processing by the main proteinase NIa-pro resulting in the production of at least ten 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). Belongs to the potyviridae genome polyprotein family.