InterPro: IPR004028 Retroviral Gag polyprotein, M

The Gag polyprotein directs the assembly and release of virus particles from infected cells. The Gag polyprotein has three domains required for activity: an N-terminal membrane-binding (M) domain that directs Gag to the plasma membrane, an interaction (I) domain involved in Gag aggregation, and a late assembly (L) domain that mediates the budding process [1]. During viral maturation, the Gag polyprotein is then cleaved into major structural proteins by the viral protease, yielding the matrix, capsid, nucleoprotein, and some smaller peptides. In Rous sarcoma virus (RSV), the M domain consists of the first 85 residues of the matrix protein. However, unlike other Gag polyproteins, the M domain of RSV Gag is not myristylated, but retains full activity [2].This domain forms an alpha helical bundle structure [3].

This entry represents the M domain of the Gag polyprotein found in avian retroviruses. This entry also identifies Gag polyproteins from several avian endogenous retroviruses, which arise when one or more copies of the retroviral genome becomes integrated into the host genome [4].