User:Nathan Roy: Difference between revisions

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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.

When MA is not bound to PI(4,5)P2 <applet load='2h3f' size='300' frame='true' align='right' caption='MA unbound to PI(4,5)P2' />, notice the alignment of helix 1, and more precisely, the orientation of Leu 8 and Glu 12. '''INSERT SCENE SHOWING RESIDUES'''

User:Nathan Roy: Difference between revisions

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Revision as of 18:45, 19 April 2009 view source Nathan Roy (talk \| contribs) 76 edits No edit summary ← Older edit		Revision as of 18:50, 19 April 2009 view source Nathan Roy (talk \| contribs) 76 edits No edit summary Newer edit →
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	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.		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.


			When MA is not bound to PI(4,5)P2 <applet load='2h3f' size='300' frame='true' align='right' caption='MA unbound to PI(4,5)P2' />, notice the alignment of helix 1, and more precisely, the orientation of Leu 8 and Glu 12. '''INSERT SCENE SHOWING RESIDUES'''