Involved in aphid transmission, cell-to-cell and systemis movement, encapsidation of the viral RNA and in the regulation of viral RNA amplification. 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.