EMD-20628

Single-particle
53.0 Å
EMD-20628 Deposition: 21/08/2019
Map released: 25/09/2019
Last modified: 29/11/2023
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links

EMD-20628

Volume 1 for truncated dimeric Cytohesin-3 (Grp1; amino acids 14-399)

EMD-20628

Single-particle
53.0 Å
EMD-20628 Deposition: 21/08/2019
Map released: 25/09/2019
Last modified: 29/11/2023
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Sample Organism: Homo sapiens
Sample: Truncated homodimer of Cytohesin-3 (Grp1, amino acids 14-399) with Inositol 1,3,4,5-tetrakis phosphate (IP4)
Fitted models: 6u3e (Avg. Q-score: 0.043)

Deposition Authors: Das S, Lambright DG
Structural Organization and Dynamics of Homodimeric Cytohesin Family Arf GTPase Exchange Factors in Solution and on Membranes.
PUBMED: 31601460
DOI: doi:10.1016/j.str.2019.09.007
ISSN: 0969-2126
ASTM: STRUE6
Abstract:
Membrane dynamic processes require Arf GTPase activation by guanine nucleotide exchange factors (GEFs) with a Sec7 domain. Cytohesin family Arf GEFs function in signaling and cell migration through Arf GTPase activation on the plasma membrane and endosomes. In this study, the structural organization of two cytohesins (Grp1 and ARNO) was investigated in solution by size exclusion-small angle X-ray scattering and negative stain-electron microscopy and on membranes by dynamic light scattering, hydrogen-deuterium exchange-mass spectrometry and guanosine diphosphate (GDP)/guanosine triphosphate (GTP) exchange assays. The results suggest that cytohesins form elongated dimers with a central coiled coil and membrane-binding pleckstrin-homology (PH) domains at opposite ends. The dimers display significant conformational heterogeneity, with a preference for compact to intermediate conformations. Phosphoinositide-dependent membrane recruitment is mediated by one PH domain at a time and alters the conformational dynamics to prime allosteric activation by Arf-GTP. A structural model for membrane targeting and allosteric activation of full-length cytohesin dimers is discussed.