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bioRxiv · 10.1101/2022.01.16.476467

Crystal Structure of Caskin1/CASK complex reveals the molecular basis of the binding specificity of CASK_CAMK domain and its binding partners

Wang, Y.·Chen, Q.·Jiang, R.·Ye, X.·Wan, J.·Li, J.·Liu, W.
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Abstract

CASK is a unique scaffold protein in the synapse system. It links numerous proteins to the pre- or post-synaptic region and is critical to the homeostasis of synaptic vesicles. The N-terminus of CASK is a calcium/calmodulin-dependent protein kinase (CAMK) domain, which has diverse functions and interacts with downstream proteins to form a scaffold platform. Caskin1 is one of the brain-specific adaptor proteins of CASK. Previous studies showed that CASK_CAMK domain interacts with Caskin1 CID domain with relatively low affinity. In this study, we re-visit this interaction by remapping the interaction boundary and solving their complex structure. Based on the structure, we systematically compared the interactions between CASK_CAMK and other binding partners. Our results showed that CAMK domain occupies the CID peptide by using its C-lobe groove (between the 1 and 2) and there is a highly conserved signature motif ({zeta}-x-{psi}-W-{psi}-x-R) in the CID domain, where {zeta} is acidic side chain containing residues, x is any amino acid residue, {psi} is hydrophobic residues, W is for tryptophan, and R is arginine. These findings allowed us to identify several new potential cytoplasmic binding partners for CASK_CAMK.

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Wang, Y., Chen, Q., Jiang, R., Ye, X., Wan, J., Li, J., Liu, W.. 2022-01-17. Crystal Structure of Caskin1/CASK complex reveals the molecular basis of the binding specificity of CASK_CAMK domain and its binding partners. https://doi.org/10.1101/2022.01.16.476467

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