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Drosophila RSK negatively regulates bouton number at the neuromuscular junction
Author(s) -
Fischer Matthias,
Raabe Thomas,
Heisenberg Martin,
Sendtner Michael
Publication year - 2009
Publication title -
developmental neurobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.716
H-Index - 129
eISSN - 1932-846X
pISSN - 1932-8451
DOI - 10.1002/dneu.20700
Subject(s) - biology , ribosomal s6 kinase , neuromuscular junction , microbiology and biotechnology , mutant , kinase , synapse , drosophila melanogaster , mapk/erk pathway , genetic screen , genetics , gene , phosphorylation , neuroscience , protein kinase b , p70 s6 kinase 1
Ribosomal S6 kinases (RSKs) are growth factor‐regulated serine‐threonine kinases participating in the RAS‐ERK signaling pathway. RSKs have been implicated in memory formation in mammals and flies. To characterize the function of RSK at the synapse level, we investigated the effect of mutations in the rsk gene on the neuromuscular junction (NMJ) in Drosophila larvae. Immunostaining revealed transgenic expressed RSK in presynaptic regions. In mutants with a full deletion or an N‐terminal partial deletion of rsk , an increased bouton number was found. Restoring the wild‐type rsk function in the null mutant with a genomic rescue construct reverted the synaptic phenotype, and overexpression of the rsk ‐cDNA in motoneurons reduced bouton numbers. Based on previous observations that RSK interacts with the Drosophila ERK homologue Rolled, genetic epistasis experiments were performed with loss‐ and gain‐of‐function mutations in Rolled. These experiments provided evidence that RSK mediates its negative effect on bouton formation at the Drosophila NMJ by inhibition of ERK signaling. © 2009 Wiley Periodicals, Inc. Develop Neurobiol 2009