Neurexins play an important role at the synapse, promoting adhesion and communication between neurons. More than 2000 neurexin isoforms are generated through a process called alternative splicing. WORKING MODEL: Neurexins are thought to be specificity factors determining neuron:neuron interactions because different splice variants are temporally and spatially expressed, splice variants bind different protein partners, and neurexins are present only on the pre-synaptic membrane. Crystallography has revealed that a specific surface is modulated by splicing in neurexin LNS/LG domains (modules in the extracellular region). OUR LONG TERM GOAL is to understand on an atomic level how neurexins help neurons recognize, adhere and communicate with each other as they form highly specific neural circuits. HYPOTHESES: Neurexins have specific features in their three-dimensional structure that enable them to work as specificity factors. Firstly, we hypothesize that neurexin LNS/LG domains contain a ligand binding surface that is regulated by two structural features 1) alternative splicing and 2) occupancy of a metal binding site by Ca2+. Secondly, we hypothesize that LNS/LG domains are arranged in space to organize areas of variation (produced through splicing) with respect to each other, adding an additional level of regulation.
SPECIFIC AIMS : (1) Delineate the ligand binding surface in neurexin LNS/LG domains (2) Assess the relevance of the Ca2+ binding site in neurexin LNS/LG domains as a molecular switch for ligand binding. (3) Reveal how alternative splicing changes epitopes of the ligand binding surface. (4) Determine the domain arrangement in the extracellular region of neurexins.
Neurexins use their atomic features to recognize and bind different partners. Neuroligin and alpha-dystroglycan, two partners that bind only specific neurexin splice variants, are associated with autism and lissencephalies. It is likely however that neurexins, through their synaptic location and essential nature, impact a much broader range of processes in humans, processes with a synaptic basis including memory, learning, drug addictive behavior and mechanisms underlying certain neurological illnesses and their psychiatric treatments. Understanding how neurexins aid synaptic function on a molecular level may ultimately guide the development of new strategies for the treatments of brain illnesses.
|Gangwar, Shanti Pal; Zhong, Xiaoying; Seshadrinathan, Suchithra et al. (2017) Molecular Mechanism of MDGA1: Regulation of Neuroligin 2:Neurexin Trans-synaptic Bridges. Neuron 94:1132-1141.e4|
|Kim, M J; Biag, J; Fass, D M et al. (2017) Functional analysis of rare variants found in schizophrenia implicates a critical role for GIT1-PAK3 signaling in neuroplasticity. Mol Psychiatry 22:417-429|
|Rudenko, Gabby (2017) Dynamic Control of Synaptic Adhesion and Organizing Molecules in Synaptic Plasticity. Neural Plast 2017:6526151|
|Lu, Zhuoyang; Reddy, M V V V Sekhar; Liu, Jianfang et al. (2016) Molecular Architecture of Contactin-associated Protein-like 2 (CNTNAP2) and Its Interaction with Contactin 2 (CNTN2). J Biol Chem 291:24133-24147|
|Meyer, Peter A; Socias, Stephanie; Key, Jason et al. (2016) Data publication with the structural biology data grid supports live analysis. Nat Commun 7:10882|
|Cates, Hannah M; Thibault, Mackenzie; Pfau, Madeline et al. (2014) Threonine 149 phosphorylation enhances ?FosB transcriptional activity to control psychomotor responses to cocaine. J Neurosci 34:11461-9|
|Lu, Zhuoyang; Wang, Yun; Chen, Fang et al. (2014) Calsyntenin-3 molecular architecture and interaction with neurexin 1?. J Biol Chem 289:34530-42|
|Pettem, Katherine L; Yokomaku, Daisaku; Luo, Lin et al. (2013) The specific *-neurexin interactor calsyntenin-3 promotes excitatory and inhibitory synapse development. Neuron 80:113-28|
|Chen, Fang; Venugopal, Vandavasi; Murray, Beverly et al. (2011) The structure of neurexin 1ýý reveals features promoting a role as synaptic organizer. Structure 19:779-89|
|Shen, Kaiser C; Kuczynska, Dorota A; Wu, Irene J et al. (2008) Regulation of neurexin 1beta tertiary structure and ligand binding through alternative splicing. Structure 16:422-31|
Showing the most recent 10 out of 11 publications