RT Journal Article SR Electronic T1 Reverse signaling by Semaphorin-6A regulates cellular aggregation and neuronal morphology JF bioRxiv FD Cold Spring Harbor Laboratory SP 036095 DO 10.1101/036095 A1 Francesc Perez-Branguli A1 Yvrick Zagar A1 Daniel K. Shanley A1 Isabella A. Graef A1 Alain Chédotal A1 Kevin J. Mitchell YR 2016 UL http://biorxiv.org/content/early/2016/01/06/036095.abstract AB The transmembrane semaphorin, Sema6A, has important roles in axon guidance, cell migration and neuronal connectivity in multiple regions of the nervous system, mediated by context-dependent interactions with plexin receptors, PlxnA2 and PlxnA4. Here, we demonstrate that Sema6A can also signal cell-autonomously, in two modes, constitutively, or in response to higher-order clustering mediated by either PlxnA2-binding or chemically induced multimerisation. Sema6A activation stimulates recruitment of Abl to the cytoplasmic domain of Sema6A and phosphorylation of this cytoplasmic tyrosine kinase, as well as phosphorylation of additional cytoskeletal regulators. Sema6A reverse signaling affects the surface area and cellular complexity of non-neuronal cells and aggregation and neurite formation of primary neurons in vitro. Sema6A also interacts with PlxnA2 in cis, which reduces binding by PlxnA2 of Sema6A in trans but not vice versa. These experiments reveal the complex nature of Sema6A biochemical functions and the molecular logic of the context-dependent interactions between Sema6A and PlxnA2.