Sandbox Reserved 1767: Difference between revisions

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RAS proteins are GTP-dependent intracellular switches that are anchored to the plasma membrane. <ref name="Liau">PMID: 35768504</ref> RAS proteins activate RAF kinases through direct binding and membrane recruitment, resulting in RAF dimerization and pathway activation <ref name="Liau">PMID: 35768504</ref>. The SMP complex has specificity for MRAS. Other RAS proteins may bind to SHOC2, but MRAS induces the complex formation with a significantly lower [https://bio.libretexts.org/Bookshelves/Biochemistry/Supplemental_Modules_(Biochemistry)/6._Lab_Notes_Part_2/6.3%3A_Ligand_binding. dissociation constant] <ref name="Liau">PMID: 35768504</ref>. There are no known membrane interacting regions on SHOC2 and PP1C, meaning the [https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Book%3A_General_Biology_(Boundless)/03%3A_Biological_Macromolecules/3.05%3A_Lipid_Molecules_-_Phospholipids#:~:text=The%20fatty%20acid%20chains%20are,the%20intracellular%20and%20extracellular%20fluid. hydrophobic fatty acid tail] on MRAS is responsible for recruiting the complex to the cell membrane allowing only for 2D movement and increasing local concentrations of the players needed in this signaling pathway <ref name="Hauseman">PMID:35830882</ref>.

A significant amount of steric overlap is seen in MRAS for the binding sites of PP1C, SHOC2, and RAF <ref name="Liau">PMID: 35768504</ref>. In '''Figure 2''', MRAS is shown in green, with the SHOC2 binding site colored cyan, the PP1C binding site colored green, and the RAF binding site shown in red on a different RAS protein. Hence, multiple RAS proteins are required for further activation of the receptor tyrosine kinase pathway <ref name="Lavoie">PMID: 35970881</ref>. Due to the significant overlap in binding domains, one MRAS molecule is needed to recruit SHOC2 and PP1C to the membrane, and another RAS molecule is needed activate RAF <ref name="Lavoie">PMID: 35970881</ref>. The ability of MRAS-GTP to cluster at the cell membrane~~</scene>~~ is a crucial capability for this protein complex. The presence of this <scene name='95/952695/413cellmemprotrusion/4'>palmitoylated tail</scene> is responsible for this anchoring to the cell membrane, similar to the hydrophobic fatty acid tail on MRAS that is responsible for recruiting SMP to the cell membrane.

A significant amount of steric overlap is seen in MRAS for the binding sites of PP1C, SHOC2, and RAF <ref name="Liau">PMID: 35768504</ref>. In '''Figure 2''', MRAS is shown in green, with the SHOC2 binding site colored cyan, the PP1C binding site colored green, and the RAF binding site shown in red on a different RAS protein. Hence, multiple RAS proteins are required for further activation of the receptor tyrosine kinase pathway <ref name="Lavoie">PMID: 35970881</ref>. Due to the significant overlap in binding domains, one MRAS molecule is needed to recruit SHOC2 and PP1C to the membrane, and another RAS molecule is needed activate RAF <ref name="Lavoie">PMID: 35970881</ref>. The ability of MRAS-GTP to cluster at the cell membrane is a crucial capability for this protein complex. The presence of this <scene name='95/952695/413cellmemprotrusion/4'>palmitoylated tail</scene> is responsible for this anchoring to the cell membrane, similar to the hydrophobic fatty acid tail on MRAS that is responsible for recruiting SMP to the cell membrane.

Sandbox Reserved 1767: Difference between revisions

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Revision as of 02:31, 17 April 2023 view source Rosa Trippel (talk \| contribs) 199 edits No edit summary ← Older edit		Revision as of 02:33, 17 April 2023 view source Rosa Trippel (talk \| contribs) 199 edits No edit summary Newer edit →
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	RAS proteins are GTP-dependent intracellular switches that are anchored to the plasma membrane. <ref name="Liau">PMID: 35768504</ref> RAS proteins activate RAF kinases through direct binding and membrane recruitment, resulting in RAF dimerization and pathway activation <ref name="Liau">PMID: 35768504</ref>. The SMP complex has specificity for MRAS. Other RAS proteins may bind to SHOC2, but MRAS induces the complex formation with a significantly lower [https://bio.libretexts.org/Bookshelves/Biochemistry/Supplemental_Modules_(Biochemistry)/6._Lab_Notes_Part_2/6.3%3A_Ligand_binding. dissociation constant] <ref name="Liau">PMID: 35768504</ref>. There are no known membrane interacting regions on SHOC2 and PP1C, meaning the [https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Book%3A_General_Biology_(Boundless)/03%3A_Biological_Macromolecules/3.05%3A_Lipid_Molecules_-_Phospholipids#:~:text=The%20fatty%20acid%20chains%20are,the%20intracellular%20and%20extracellular%20fluid. hydrophobic fatty acid tail] on MRAS is responsible for recruiting the complex to the cell membrane allowing only for 2D movement and increasing local concentrations of the players needed in this signaling pathway <ref name="Hauseman">PMID:35830882</ref>.		RAS proteins are GTP-dependent intracellular switches that are anchored to the plasma membrane. <ref name="Liau">PMID: 35768504</ref> RAS proteins activate RAF kinases through direct binding and membrane recruitment, resulting in RAF dimerization and pathway activation <ref name="Liau">PMID: 35768504</ref>. The SMP complex has specificity for MRAS. Other RAS proteins may bind to SHOC2, but MRAS induces the complex formation with a significantly lower [https://bio.libretexts.org/Bookshelves/Biochemistry/Supplemental_Modules_(Biochemistry)/6._Lab_Notes_Part_2/6.3%3A_Ligand_binding. dissociation constant] <ref name="Liau">PMID: 35768504</ref>. There are no known membrane interacting regions on SHOC2 and PP1C, meaning the [https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Book%3A_General_Biology_(Boundless)/03%3A_Biological_Macromolecules/3.05%3A_Lipid_Molecules_-_Phospholipids#:~:text=The%20fatty%20acid%20chains%20are,the%20intracellular%20and%20extracellular%20fluid. hydrophobic fatty acid tail] on MRAS is responsible for recruiting the complex to the cell membrane allowing only for 2D movement and increasing local concentrations of the players needed in this signaling pathway <ref name="Hauseman">PMID:35830882</ref>.

	A significant amount of steric overlap is seen in MRAS for the binding sites of PP1C, SHOC2, and RAF <ref name="Liau">PMID: 35768504</ref>. In '''Figure 2''', MRAS is shown in green, with the SHOC2 binding site colored cyan, the PP1C binding site colored green, and the RAF binding site shown in red on a different RAS protein. Hence, multiple RAS proteins are required for further activation of the receptor tyrosine kinase pathway <ref name="Lavoie">PMID: 35970881</ref>. Due to the significant overlap in binding domains, one MRAS molecule is needed to recruit SHOC2 and PP1C to the membrane, and another RAS molecule is needed activate RAF <ref name="Lavoie">PMID: 35970881</ref>. The ability of MRAS-GTP to cluster at the cell membrane~~</scene>~~ is a crucial capability for this protein complex. The presence of this <scene name='95/952695/413cellmemprotrusion/4'>palmitoylated tail</scene> is responsible for this anchoring to the cell membrane, similar to the hydrophobic fatty acid tail on MRAS that is responsible for recruiting SMP to the cell membrane.		A significant amount of steric overlap is seen in MRAS for the binding sites of PP1C, SHOC2, and RAF <ref name="Liau">PMID: 35768504</ref>. In '''Figure 2''', MRAS is shown in green, with the SHOC2 binding site colored cyan, the PP1C binding site colored green, and the RAF binding site shown in red on a different RAS protein. Hence, multiple RAS proteins are required for further activation of the receptor tyrosine kinase pathway <ref name="Lavoie">PMID: 35970881</ref>. Due to the significant overlap in binding domains, one MRAS molecule is needed to recruit SHOC2 and PP1C to the membrane, and another RAS molecule is needed activate RAF <ref name="Lavoie">PMID: 35970881</ref>. The ability of MRAS-GTP to cluster at the cell membrane is a crucial capability for this protein complex. The presence of this <scene name='95/952695/413cellmemprotrusion/4'>palmitoylated tail</scene> is responsible for this anchoring to the cell membrane, similar to the hydrophobic fatty acid tail on MRAS that is responsible for recruiting SMP to the cell membrane.