The structural basis of Arf effector specificity: the crystal structure of ARF6 in a complex with JIP4.
The JNK-interacting proteins, JIP3 and JIP4, are specific effectors of the small GTP-binding protein ARF6. The interaction of ARF6-GTP with the second leucine zipper (LZII) domains of JIP3/JIP4 regulates the binding of JIPs to kinesin-1 and dynactin. Here, we report the crystal structure of ARF6-GTP bound to the JIP4-LZII at 1.9 A resolution. The complex is a heterotetramer with dyad symmetry arranged in an ARF6-(JIP4)(2)-ARF6 configuration. Comparison of the ARF6-JIP4 interface with the equivalent region of ARF1 shows the structural basis of JIP4's specificity for ARF6. Using site-directed mutagenesis and surface plasmon resonance, we further show that non-conserved residues at the switch region borders are the key structural determinants of JIP4 specificity. A structure-derived model of the association of the ARF6-JIP3/JIP4 complex with membranes shows that the JIP4-LZII coiled-coil should lie along the membrane to prevent steric hindrances, resulting in only one ARF6 molecule bound. Such a heterotrimeric complex gives insights to better understand the ARF6-mediated motor switch regulatory function.
Isabet
Tatiana
T
Institut Curie, Centre de Recherche, Paris, France.
Montagnac
Guillaume
G
Regazzoni
Karine
K
Raynal
Bertrand
B
El Khadali
Fatima
F
England
Patrick
P
Franco
Michel
M
Chavrier
Philippe
P
Houdusse
Anne
A
Ménétrey
Julie
J
D000089982:ADP-Ribosylation Factor 6; D020727:ADP-Ribosylation Factors / Q000737:chemistry*; D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry*; D000595:Amino Acid Sequence; D019281:Dimerization; D000072159:Dynactin Complex; D006160:Guanosine Triphosphate / Q000378:metabolism; D016547:Kinesins / Q000737:chemistry*; D008869:Microtubule-Associated Proteins / Q000737:chemistry*; D008954:Models, Biological; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D020349:Surface Plasmon Resonance
D000089982:ADP-Ribosylation Factor 6; D048868:Adaptor Proteins, Signal Transducing; D000072159:Dynactin Complex; D008869:Microtubule-Associated Proteins; C111047:SPAG9 protein, human; D006160:Guanosine Triphosphate; D016547:Kinesins; D020727:ADP-Ribosylation Factors; C000715348:ARF6 protein, human