biostudies-literaturePlatsaki SEuropean Research Council16267-16279https://www.ebi.ac.uk/biostudies/studies/S-EPMC7705314biostudies-literatureUnknown295(48)Punctin/MADD-4, a member of the ADAMTSL extracellular matrix protein family, was identified as an anterograde synaptic organizer in the nematode <i>Caenorhabditis elegans.</i> At GABAergic neuromuscular junctions, the short isoform MADD-4B binds the ectodomain of neuroligin NLG-1, itself a postsynaptic organizer of inhibitory synapses. To identify the molecular bases of their partnership, we generated recombinant forms of the two proteins and carried out a comprehensive biochemical and biophysical study of their interaction, complemented by an <i>in vivo</i> localization study. We show that spontaneous proteolysis of MADD-4B first generates a shorter N-MADD-4B form, which comprises four thrombospondin (TSP) domains and one Ig-like domain and binds NLG-1. A second processing event eliminateThe Journal of biological chemistryThe Ig-like domain of Punctin/MADD-4 is the primary determinant for interaction with the ectodomain of neuroligin NLG-1.PMC7705314695295Platsaki SMarchot PDelauzun VBourne YBessereau JLZhou XPinan-Lucarre BFourquet PTu HMansuelle PfalseThe Ig-like domain of Punctin/MADD-4 is the primary determinant for interaction with the ectodomain of neuroligin NLG-1.Punctin/MADD-4, a member of the ADAMTSL extracellular matrix protein family, was identified as an anterograde synaptic organizer in the nematode <i>Caenorhabditis elegans.</i> At GABAergic neuromuscular junctions, the short isoform MADD-4B binds the ectodomain of neuroligin NLG-1, itself a postsynaptic organizer of inhibitory synapses. To identify the molecular bases of their partnership, we generated recombinant forms of the two proteins and carried out a comprehensive biochemical and biophysical study of their interaction, complemented by an <i>in vivo</i> localization study. We show that spontaneous proteolysis of MADD-4B first generates a shorter N-MADD-4B form, which comprises four thrombospondin (TSP) domains and one Ig-like domain and binds NLG-1. A second processing event eliminate2020-01-01T00:00:00Z2020 Nov2026-04-29T09:09:48.128Z2022-02-11T13:12:29.421ZS-EPMC77053143292895910.1074/jbc.ra120.01459110.1074/jbc.RA120.014591