InterPro: IPR010999 Retroviral matrix, N-terminal

Retroviral matrix proteins (or major core proteins) are components of envelope-associated capsids, which line the inner surface of virus envelopes and are associated with viral membranes [1]. Matrix proteins are produced as part of Gag precursor polyproteins. During viral maturation, the Gag polyprotein is cleaved into major structural proteins by the viral protease, yielding the matrix (MA), capsid (CA), nucleocapsid (NC), and some smaller peptides. Gag-derived proteins govern the entire assembly and release of the virus particles, with matrix proteins playing key roles in Gag stability, capsid assembly, transport and budding. Although matrix proteins from different retroviruses appear to perform similar functions and can have similar structural folds, their primary sequences can be very different.

This entry represents structurally homologous matrix proteins from different retroviruses, their structure consisting of four-five alpha helices in a right-handed superhelix. Retroviral matrix proteins bearing this structure have been isolated from Human immunodeficiency virus (HIV), Simian immunodeficiency virus (SIV-cpz), Human T-lymphotropic virus 1, Human T-cell leukemia virus 2 (HTLV-2), Mason-Pfizer monkey virus (MPMV) (Simian Mason-Pfizer virus), Rous sarcoma virus (RSV), Equine infectious anemia virus (EIAV), and Moloney murine leukemia virus (MoMLV). This entry also identifies matrix proteins from several eukaryotic endogenous retroviruses, which arise when one or more copies of the retroviral genome becomes integrated into the host genome [2].