Sandbox Reserved 1788: Difference between revisions
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==PP1C== | ==PP1C== | ||
<scene name='95/952717/Pp1c/1'>PP1C</scene> is a catalytic protein. After forming a ternary complex, the <scene name='95/952717/Pp1c_hydrophobic_patch/1'>hydrophobic active site</scene> on the protein interacts with Raf to act as a phosphatase and dephosphorylate Ser 259. PP1C's active site is adjacent to a hydrophobic patch. It's theorized that the hydrophobic patch binds to the C-terminal of N-terminal phosphoserine of RAF, the target for dephosphorylation. PP1C can act as a phosphatase in the absence of SHOC2 but PP1C lasks intrinsic substrate selectively. So SMP complex formation is necessary for PP1C specificity to RAF. | <scene name='95/952717/Pp1c/1'>PP1C</scene> is a catalytic protein. After forming a ternary complex, the <scene name='95/952717/Pp1c_hydrophobic_patch/1'>hydrophobic active site</scene> on the protein interacts with Raf to act as a phosphatase and dephosphorylate Ser 259. PP1C's active site is adjacent to a hydrophobic patch. It's theorized that the hydrophobic patch binds to the C-terminal of N-terminal phosphoserine of RAF, the target for dephosphorylation. PP1C can act as a phosphatase in the absence of SHOC2 but PP1C lasks intrinsic substrate selectively. So SMP complex formation is necessary for PP1C specificity to RAF. | ||
[[Image:ActiveSiteProto.png|500 px|]] | |||
== MRAS == | == MRAS == | ||
<scene name='95/952717/Mras/2'>MRAS</scene> is a membrane-bound structure that aids the complex in localizing near other structures such as the RAS-RAF-MAPK complex in order to initiate downstream signaling. In its inactive state, MRAS is bound to GDP. When signaled by growth factors, the GDP is exchanged for GTP. The now <scene name='95/952718/Zoom_in_gtp/1'>GTP bound MRAS</scene> undergoes a conformational change of the <scene name='95/952716/Ras-switch-zoomed/1'>switch I and switch II regions</scene>. This conformational change activates the protein allowing it to bind with the SHOC2-PP1C complex. Without the conformational change when GDP is exchanged to GTP, the GDP-MRAS wouldn't be able to bind to SHOC2 because of steric clashing. In comparison to other RAS proteins, MRAS has a greater affinity for the SHOC2-PP1C complex. MRAS engages the SHOC2-PP1C complex and RAF on the same surface indicating that for RAF signaling two separate active MRASs are needed. Having two MRASs also help with the co-localization of PP1C to the NTpS region on RAF. | <scene name='95/952717/Mras/2'>MRAS</scene> is a membrane-bound structure that aids the complex in localizing near other structures such as the RAS-RAF-MAPK complex in order to initiate downstream signaling. In its inactive state, MRAS is bound to GDP. When signaled by growth factors, the GDP is exchanged for GTP. The now <scene name='95/952718/Zoom_in_gtp/1'>GTP bound MRAS</scene> undergoes a conformational change of the <scene name='95/952716/Ras-switch-zoomed/1'>switch I and switch II regions</scene>. This conformational change activates the protein allowing it to bind with the SHOC2-PP1C complex. Without the conformational change when GDP is exchanged to GTP, the GDP-MRAS wouldn't be able to bind to SHOC2 because of steric clashing. In comparison to other RAS proteins, MRAS has a greater affinity for the SHOC2-PP1C complex. MRAS engages the SHOC2-PP1C complex and RAF on the same surface indicating that for RAF signaling two separate active MRASs are needed. Having two MRASs also help with the co-localization of PP1C to the NTpS region on RAF. | ||