Scaffold proteins are key players in many signaling pathways where they ensure spatial and temporal control of molecular interactions by simultaneous tethering of multiple signaling components. The protein JIP1 acts as a scaffold within the c-Jun N-terminal kinase (JNK) signaling pathway, one of the three main mitogen-activated protein kinase (MAPK) pathways. JIP1 has a long, intrinsically disordered N-terminal domain consisting of 450 amino acids, for which the molecular mechanisms associated with its function remains elusive.
Here, we provide an atomic resolution structural description of the JIP1 tail, and we study its interaction with the kinase JNK1. Using NMR spectroscopy, we show that JNK1 not only engages with the well-known docking site motif (D-motif) of JIP1, but also interacts with a noncanonical F-motif. We determine the crystal structure of the JIP1-JNK1 complex at 2.35 Å resolution revealing a bipartite binding mode of JIP1. Our work provides insights into the sequence determinants of F-motifs suggesting that these motifs may be more prevalent in JNK substrates than previously recognized. More broadly, our study highlights the power of NMR spectroscopy in uncovering kinase interaction motifs within disordered scaffold proteins, and it paves the way for atomic-resolution interaction studies of JIP1 with its multitude of interaction partners.
Researchers from IBS (SIGNAL, FDP and EPIGEN groups), IAB (Andrés Palencia’s group) and the University of Massachusetts (Roger Davis’ group) have joined forces to characterise, at the atomic level, the interaction between the disordered domain of JIP1 and JNK kinase. Using NMR spectroscopy, they show that JNK1 not only engages with the well-known docking site motif (D-motif) of JIP1, but also interacts with a noncanonical F-motif. The crystallographic structure of the JIP1-JNK1 complex, resolved at 2.35 Å, revealed a bipartite interaction mode in which JIP1 wraps around JNK. The D-motif remains in a disordered conformation, while the F-motif adopts an alpha-helix structure during its interaction with JNK. This binding mode has important implications for understanding the multisite phosphorylation of JIP1 by JNK – a modification known to regulate many functions of this protein.
Bipartite binding of the intrinsically disordered scaffold protein JIP1 to the kinase JNK1. Orand T, Delaforge E, Lee A, Kragelj J, Tengo M, Tengo L, Blackledge M, Boeri Erba
E, Davis RJ, Palencia A, Jensen MR. Proceedings of the National Academy of Sciences of The United States Of America 2025 ;122:e2419915122
Contact : Malene Ringkjobing Jensen (IBS/Structural Dynamics of Signalling Complexes Group)