8.A.117.  The Neuroligin (Nlg) Family 

Activity-dependent proteolytic cleavage of neuroligins revealed a broader role for neuroligins than just synaptic 'glue'. The cleaved extracellular fragments of neuroligins may promote glioma formation. Cell signaling mediated by the cleavage products of neuroligins suggest novel and important roles for neuroligins in neuro-glial signaling. Neuroligin isoforms are dynamically regulated by posttranslational events including phosphorylation, glycosylation and activity-dependent cleavage (Jeong et al. 2017). It appears that neuroligins are homologous to many esterases, and therefore, they may have esterase activity.

Physical interactions in the synapse, mediated by synaptic adhesion molecules such as neiroligins, are essential for synaptogenesis. The regulation of adhesion molecules and their interactions with other synaptic proteins affect synapse formation and synaptic function. Bemben et al. 2015 reviewed the neuroligins, which bind to their presynaptic partner neurexin across the synaptic cleft. A structural overview of neuroligins, including their intermolecular interactions and molecular modifications that occur within a synapse as well as their physiological functions were presented by Bemben et al. 2015. neuroligins are constituents of GABAA receptor complexes (Tomita 2019).