Abstract
GCC185 is a large coiled-coil protein at the trans Golgi network that is required for receipt of transport vesicles inbound from late endosomes and for anchoring noncentrosomal microtubules that emanate from the Golgi. Here, we demonstrate that recruitment of GCC185 to the Golgi is mediated by two Golgi-localized small GTPases of the Rab and Arl families. GCC185 binds Rab6, and mutation of residues needed for Rab binding abolishes Golgi localization. The crystal structure of Rab6 bound to the GCC185 Rab-binding domain reveals that Rab6 recognizes a two-fold symmetric surface on a coiled coil immediately adjacent to a C-terminal GRIP domain. Unexpectedly, Rab6 binding promotes association of Arl1 with the GRIP domain. We present a structure-derived model for dual GTPase membrane attachment that highlights the potential ability of Rab GTPases to reach binding partners at a significant distance from the membrane via their unstructured and membrane-anchored, hypervariable domains.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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ADP-Ribosylation Factors / chemistry
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ADP-Ribosylation Factors / genetics
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ADP-Ribosylation Factors / isolation & purification
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ADP-Ribosylation Factors / metabolism*
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Alanine / metabolism
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Amino Acid Substitution
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Binding Sites
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Crystallography, X-Ray
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Dimerization
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Glutathione Transferase / metabolism
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Golgi Matrix Proteins
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HeLa Cells
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Humans
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Hydrophobic and Hydrophilic Interactions
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Membrane Proteins / chemistry
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Membrane Proteins / genetics
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Membrane Proteins / isolation & purification
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Membrane Proteins / metabolism*
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Models, Biological
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Models, Chemical
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Models, Molecular
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Plasmids
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Protein Binding
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Protein Structure, Secondary
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Protein Structure, Tertiary
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RNA Interference
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RNA, Small Interfering / metabolism
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Recombinant Fusion Proteins / chemistry
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Recombinant Fusion Proteins / metabolism
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Transfection
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X-Ray Diffraction
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rab GTP-Binding Proteins / chemistry
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rab GTP-Binding Proteins / genetics
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rab GTP-Binding Proteins / isolation & purification
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rab GTP-Binding Proteins / metabolism*
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trans-Golgi Network / metabolism
Substances
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GCC2 protein, human
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Golgi Matrix Proteins
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Membrane Proteins
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RNA, Small Interfering
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Recombinant Fusion Proteins
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Glutathione Transferase
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ADP-ribosylation factor related proteins
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ADP-Ribosylation Factors
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rab GTP-Binding Proteins
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Alanine