RESUMEN
Synapse formation requires the precise coordination of axon elongation, cytoskeletal stability, and diverse modes of cell signaling. The underlying mechanisms of this interplay, however, remain unclear. Here, we demonstrate that Strip, a component of the striatin-interacting phosphatase and kinase (STRIPAK) complex that regulates these processes, is required to ensure the proper development of synaptic boutons at the Drosophila neuromuscular junction. In doing so, Strip negatively regulates the activity of the Hippo (Hpo) pathway, an evolutionarily conserved regulator of organ size whose role in synapse formation is currently unappreciated. Strip functions genetically with Enabled, an actin assembly/elongation factor and the presumptive downstream target of Hpo signaling, to modulate local actin organization at synaptic termini. This regulation occurs independently of the transcriptional co-activator Yorkie, the canonical downstream target of the Hpo pathway. Our study identifies a previously unanticipated role of the Strip-Hippo pathway in synaptic development, linking cell signaling to actin organization.
Asunto(s)
Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Péptidos y Proteínas de Señalización Intracelular/genética , Proteínas del Tejido Nervioso/genética , Unión Neuromuscular/metabolismo , Terminales Presinápticos/metabolismo , Proteínas Serina-Treonina Quinasas/genética , Transducción de Señal , Citoesqueleto de Actina/metabolismo , Citoesqueleto de Actina/ultraestructura , Actinas/genética , Actinas/metabolismo , Animales , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/crecimiento & desarrollo , Drosophila melanogaster/metabolismo , Regulación del Desarrollo de la Expresión Génica , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Larva/genética , Larva/crecimiento & desarrollo , Larva/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Neurogénesis/genética , Unión Neuromuscular/crecimiento & desarrollo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Terminales Presinápticos/ultraestructura , Proteínas Serina-Treonina Quinasas/metabolismo , Transactivadores/genética , Transactivadores/metabolismo , Proteínas Señalizadoras YAPRESUMEN
During neural development, regulation of microtubule stability is essential for proper morphogenesis of neurons. Recently, the striatin-interacting phosphatase and kinase (STRIPAK) complex was revealed to be involved in diverse cellular processes. However, there is little evidence that STRIPAK components regulate microtubule dynamics, especially in vivo. Here, we show that one of the core STRIPAK components, Strip, is required for microtubule organization during neuronal morphogenesis. Knockdown of Strip causes a decrease in the level of acetylated α-tubulin in Drosophila S2 cells, suggesting that Strip influences the stability of microtubules. We also found that Strip physically and genetically interacts with tubulin folding cofactor D (TBCD), an essential regulator of α- and ß-tubulin heterodimers. Furthermore, we demonstrate the genetic interaction between strip and Down syndrome cell adhesion molecule (Dscam), a cell surface molecule that is known to work with TBCD. Thus, we propose that Strip regulates neuronal morphogenesis by affecting microtubule stability.
