Hiv-1 gag: Difference between revisions

Newer edit →

Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

Nathan Roy, Michal Harel, Alexander Berchansky

Revision as of 06:56, 23 April 2009 view source Nathan Roy (talk \| contribs) 76 edits New page: ==HIV-1 Gag== ---- The HIV-1 Gag protein is the major structural protein required for virus assembly. It is synthesized as a polyprotein in the cytosol of an infected cell, and contains ...		Revision as of 17:20, 23 April 2009 view source Nathan Roy (talk \| contribs) 76 edits No edit summary Newer edit →
Line 11:		Line 11:


	The MA domain (also called Matrix) is essential for proper targeting of Gag (and thus virus release) to distinct locations on the plasma membrane. The MA domain is myristylated post translationally, which is important for a stable association with the plasma membrane. Perhaps just as important for proper virus assembly, is the interaction of MA with phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). It has long been known that HIV-1 budding occurs at sites rich in PI(4,5)P2 and cholesterol (lipid rafts, and tetraspanin enriched microdomains, TEMs), probably to ensure proper virus budding localized to the plasma membrane (elimination of PI(4,5)P2 causes virions to assembly at intracellular endosomes). More recently, structural analysis of MA has revealed a myristylation switch that allows ~~exposer~~ of the myristyl group to the plasma membrane only upon binding of MA to PI(4,5)P2, a mechanism ensuring proper localization of Gag to rafts within the plasma membrane.<applet load='2H3I_mono1.pdb' size='300' frame='true' align='right' caption=' FIGURE 1. MA unbound to PI(4,5)P2' scene=''/>		The MA domain (also called Matrix) is essential for proper targeting of Gag (and thus virus release) to distinct locations on the plasma membrane. The MA domain is myristylated post translationally, which is important for a stable association with the plasma membrane. Perhaps just as important for proper virus assembly, is the interaction of MA with phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). It has long been known that HIV-1 budding occurs at sites rich in PI(4,5)P2 and cholesterol (lipid rafts, and tetraspanin enriched microdomains, TEMs), probably to ensure proper virus budding localized to the plasma membrane (elimination of PI(4,5)P2 causes virions to assembly at intracellular endosomes). More recently, structural analysis of MA has revealed a myristylation switch that allows exposure of the myristyl group to the plasma membrane only upon binding of MA to PI(4,5)P2, a mechanism ensuring proper localization of Gag to rafts within the plasma membrane.<applet load='2H3I_mono1.pdb' size='300' frame='true' align='right' caption=' FIGURE 1. MA unbound to PI(4,5)P2' scene=''/>