The products of the Gag polyproteins of infectious retroviruses perform highly complex orchestrated tasks during the assembly, budding, maturation, and infection stages of the viral replication cycle. During viral assembly, the proteins form membrane associations and self-associations that ultimately result in budding of an immature virion from the infected cell. Gag precursors also function during viral assembly to selectively bind and package two plus strands of genomic RNA. Endogenous Gag proteins may have kept, lost or modified their original function during evolution. Cytoplasmic membrane (in a transfection system). This protein is synthesized as a Gag polypeptide and as a Gag-Pro-Pol polyprotein. The later is the precursor of the Pro and Pol proteins. It is thought, by similarity with type-B retroviruses, to be generated by -1 frameshifts occurring at the Gag-Pro and Pro-Pol genes boundaries. HERV-K Gag polyprotein contains regions homologous to the matrix (MA), capsid (CA) and nucleocapsid (NC) proteins from infectious retroviruses. Evidence suggests that HERV-K(HML-2) Gag polyprotein can be cleaved into mature MA, CA and NC under certain circumstances. However, the exact boundaries as well as the size of processed Gag proteins have not been precisely determined yet. Myristoylation is essential for retroviral assembly. Alteration of the glycine residue leads to a block in the budding of particles and an accumulation of Gag inside the cell (By similarity). Specific enzymatic cleavages may yield mature proteins. Insertional polymorphism. Provirus present in 29% of tested individuals. Belongs to the beta type-B retroviral Gag protein family. HERV class-II K(HML-2) gag subfamily.