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Publication Abstract from PubMed

SALM5, a synaptic adhesion molecule implicated in autism, induces presynaptic differentiation through binding to the LAR family receptor protein tyrosine phosphatases (LAR-RPTPs) that have been highlighted as presynaptic hubs for synapse formation. The mechanisms underlying SALM5/LAR-RPTP interaction remain unsolved. Here we report crystal structures of human SALM5 LRR-Ig alone and in complex with human PTPdelta Ig1-3 (MeA(-)). Distinct from other LAR-RPTP ligands, SALM5 mainly exists as a dimer with LRR domains from two protomers packed in an antiparallel fashion. In the 2:2 heterotetrameric SALM5/PTPdelta complex, a SALM5 dimer bridges two separate PTPdelta molecules. Structure-guided mutations and heterologous synapse formation assays demonstrate that dimerization of SALM5 is prerequisite for its functionality in inducing synaptic differentiation. This study presents a structural template for the SALM family and reveals a mechanism for how a synaptic adhesion molecule directly induces cis-dimerization of LAR-RPTPs into higher-order signaling assembly.

Structural basis of SALM5-induced PTPdelta dimerization for synaptic differentiation.,Lin Z, Liu J, Ding H, Xu F, Liu H Nat Commun. 2018 Jan 18;9(1):268. doi: 10.1038/s41467-017-02414-2. PMID:29348579^[3]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.