2qa7
Crystal structure of Huntingtin-interacting protein 1 (HIP1) coiled-coil domain with a basic surface suitable for HIP-protein interactor (HIPPI)
Structural highlights
DiseaseHIP1_HUMAN Note=A chromosomal aberration involving HIP1 is found in a form of chronic myelomonocytic leukemia (CMML). Translocation t(5;7)(q33;q11.2) with PDGFRB. The chimeric HIP1-PDGFRB transcript results from an in-frame fusion of the two genes. The reciprocal PDGFRB-HIP1 transcript is not expressed. FunctionHIP1_HUMAN Plays a role in clathrin-mediated endocytosis and trafficking. Involved in regulating AMPA receptor trafficking in the central nervous system in an NMDA-dependent manner. Enhances androgen receptor (AR)-mediated transcription. May act as a proapoptotic protein that induces cell death by acting through the intrinsic apoptosis pathway. Binds 3-phosphoinositides (via ENTH domain). May act through the ENTH domain to promote cell survival by stabilizing receptor tyrosine kinases following ligand-induced endocytosis. May play a functional role in the cell filament networks. May be required for differentiation, proliferation, and/or survival of somatic and germline progenitors.[1] [2] [3] [4] [5] [6] [7] [8] 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 PubMedHuntington's disease is a genetic neurological disorder that is triggered by the dissociation of the huntingtin protein (htt) from its obligate interaction partner Huntingtin-interacting protein 1 (HIP1). The release of the huntingtin protein permits HIP1 protein interactor (HIPPI) to bind to its recognition site on HIP1 to form a HIPPI/HIP1 complex that recruits procaspase-8 to begin the process of apoptosis. The interaction module between HIPPI and HIP1 was predicted to resemble a death-effector domain. Our 2.8-A crystal structure of the HIP1 371-481 subfragment that includes F432 and K474, which is important for HIPPI binding, is not a death-effector domain but is a partially opened coiled coil. The HIP1 371-481 model reveals a basic surface that we hypothesize to be suitable for binding HIPPI. There is an opened region next to the putative HIPPI site that is highly negatively charged. The acidic residues in this region are highly conserved in HIP1 and a related protein, HIP1R, from different organisms but are not conserved in the yeast homologue of HIP1, sla2p. We have modeled approximately 85% of the coiled-coil domain by joining our new HIP1 371-481 structure to the HIP1 482-586 model (Protein Data Bank code: 2NO2). Finally, the middle of this coiled-coil domain may be intrinsically flexible and suggests a new interaction model where HIPPI binds to a U-shaped HIP1 molecule. Crystal structure at 2.8 A of Huntingtin-interacting protein 1 (HIP1) coiled-coil domain reveals a charged surface suitable for HIP1 protein interactor (HIPPI).,Niu Q, Ybe JA J Mol Biol. 2008 Feb 1;375(5):1197-205. Epub 2007 Nov 22. PMID:18155047[9] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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