3ea5
From Proteopedia
Kap95p Binding Induces the Switch Loops of RanGDP to adopt the GTP-bound Conformation: Implications for Nuclear Import Complex Assembly Dynamics
Structural highlights
Function[RAN_HUMAN] GTP-binding protein involved in nucleocytoplasmic transport. Required for the import of protein into the nucleus and also for RNA export. Involved in chromatin condensation and control of cell cycle (By similarity). The complex with BIRC5/ survivin plays a role in mitotic spindle formation by serving as a physical scaffold to help deliver the RAN effector molecule TPX2 to microtubules. Acts as a negative regulator of the kinase activity of VRK1 and VRK2.[1] [2] [3] [4] Enhances AR-mediated transactivation. Transactivation decreases as the poly-Gln length within AR increases.[5] [6] [7] [8] [IMB1_YEAST] Required for nuclear protein import and mediates docking of import substrate to distinct nucleoporins. Serves a receptor for nuclear localization signals. Mediates the nuclear import of histones H2A and H2B.[9] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe asymmetric distribution of the nucleotide-bound state of Ran across the nuclear envelope is crucial for determining the directionality of nuclear transport. In the nucleus, Ran is primarily in the guanosine 5'-triphosphate (GTP)-bound state, whereas in the cytoplasm, Ran is primarily guanosine 5'-diphosphate (GDP)-bound. Conformational changes within the Ran switch I and switch II loops are thought to modulate its affinity for importin-beta. Here, we show that RanGDP and importin-beta form a stable complex with a micromolar dissociation constant. This complex can be dissociated by importin-beta binding partners such as importin-alpha. Surprisingly, the crystal structure of the Kap95p-RanGDP complex shows that Kap95p induces the switch I and II regions of RanGDP to adopt a conformation that resembles that of the GTP-bound form. The structure of the complex provides insights into the structural basis for the gradation of affinities regulating nuclear protein transport. Kap95p binding induces the switch loops of RanGDP to adopt the GTP-bound conformation: implications for nuclear import complex assembly dynamics.,Forwood JK, Lonhienne TG, Marfori M, Robin G, Meng W, Guncar G, Liu SM, Stewart M, Carroll BJ, Kobe B J Mol Biol. 2008 Nov 21;383(4):772-82. Epub 2008 Aug 7. PMID:18708071[10] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
| ||||||||||||||||||||
