Sandbox Reserved 1710: Difference between revisions

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=== Closed Conformation ===
=== Closed Conformation ===
In the <scene name='90/904315/Closed/3'>closed, inactive conformation</scene>, the GRD and Sec14-PH domains are rotated so Ras cannot bind. In this conformation, the GRD and Sec14-PH are inaccessible and inactive. Neurofibromin is held in the inactive state by a <scene name='90/904315/Closed_triade/7'>triad</scene> consisting of residues Cys 1032, His 1558, and His 1576 that form a transition metal-binding site with zinc. The rigid organization of the <scene name='90/904315/Closed_triade/8'>triad in closed conformation</scene> keeps the GRD domain packed tightly on top of the Heat Arms in the Neurofibromin core. This tight compaction sterically occludes Neurofibromin from associating with Ras. In its active form, Ras and Neurofibromin will associate via an <scene name='90/904316/Arg_finger/2'>Arginine finger</scene> (Arg 1276). However, the steric hindrance from the Neurofibromin core in the closed conformation inhibits this association. Therefore, in the closed conformation, neurofibromin cannot catalyze GTP hydrolysis by Ras and Ras continues to signal for cell growth and proliferation.<ref name="Naschberger">PMID:34707296</ref>
In the <scene name='90/904315/Closed/3'>closed, inactive conformation</scene>, the GRD and Sec14-PH domains are rotated so Ras cannot bind. In this conformation, the GRD and Sec14-PH are inaccessible and inactive. Neurofibromin is held in the inactive state by a <scene name='90/904315/Closed_triade/7'>triad</scene> consisting of residues Cys 1032, His 1558, and His 1576 that form a transition metal-binding site with zinc. The rigid organization of the <scene name='90/904315/Closed_triade/8'>triad in closed conformation</scene> keeps the GRD domain packed tightly on top of the Heat Arms in the Neurofibromin core. This tight compaction sterically occludes Neurofibromin from <scene name='90/904315/Closed_with_ras/2'>associating with Ras.</scene> In its active form, Ras and Neurofibromin will associate via an (Arg 1276). However, the steric hindrance from the Neurofibromin core in the closed conformation inhibits this association. Therefore, in the closed conformation, neurofibromin cannot catalyze GTP hydrolysis by Ras and Ras continues to signal for cell growth and proliferation.<ref name="Naschberger">PMID:34707296</ref>


=== Open Conformation ===
=== Open Conformation ===
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[[Image:Domain Rotation.jpg|500 px|left|thumb|Figure 4: Rotation of the GRD and Sec14-PH domains from the closed conformation (7PGR) of neurofibromin to the open conformation (7PGT) of neurofibromin to allow Ras binding. The GRD rotates -130° and the Sec14-PH domain rotates -90°]]
[[Image:Domain Rotation.jpg|500 px|left|thumb|Figure 4: Rotation of the GRD and Sec14-PH domains from the closed conformation (7PGR) of neurofibromin to the open conformation (7PGT) of neurofibromin to allow Ras binding. The GRD rotates -130° and the Sec14-PH domain rotates -90°]]


== Disease and Medical Relevance ==
== Disease and Medical Relevance ==
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Mutations in the NF1 gene have been found in sporadic cancers such as [https://en.wikipedia.org/wiki/Glioblastoma glioblastoma], [https://en.wikipedia.org/wiki/Neuroblastoma neuroblastoma], [https://en.wikipedia.org/wiki/Lung_cancer lung cancer], [https://en.wikipedia.org/wiki/Ovarian_cancer ovarian cancer], and [https://en.wikipedia.org/wiki/Breast_cancer breast cancer]. Researchers are still unsure as to whether biallelic loss of NF1 is common or if it is only a hemizygous loss of the gene that contributes to the growth progression of certain sporadic tumors.<ref name="Ratner">PMID:25877329</ref>
Mutations in the NF1 gene have been found in sporadic cancers such as [https://en.wikipedia.org/wiki/Glioblastoma glioblastoma], [https://en.wikipedia.org/wiki/Neuroblastoma neuroblastoma], [https://en.wikipedia.org/wiki/Lung_cancer lung cancer], [https://en.wikipedia.org/wiki/Ovarian_cancer ovarian cancer], and [https://en.wikipedia.org/wiki/Breast_cancer breast cancer]. Researchers are still unsure as to whether biallelic loss of NF1 is common or if it is only a hemizygous loss of the gene that contributes to the growth progression of certain sporadic tumors.<ref name="Ratner">PMID:25877329</ref>


<scene name='90/904315/Closed_with_ras/2'>Closed with Ras</scene>
 
<scene name='90/904315/Openwithras/1'>Open with Ras</scene>
<scene name='90/904315/Openwithras/1'>Open with Ras</scene>


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