@article {46422,
	title = {Negative regulation of active zone assembly by a newly identified SR protein kinase.},
	journal = {PLoS Biology},
	volume = {7},
	year = {2009},
	month = {2009 Sep},
	pages = {e1000193},
	abstract = {<p>Presynaptic, electron-dense, cytoplasmic protrusions such as the T-bar (Drosophila) or ribbon (vertebrates) are believed to facilitate vesicle movement to the active zone (AZ) of synapses throughout the nervous system. The molecular composition of these structures including the T-bar and ribbon are largely unknown, as are the mechanisms that specify their synapse-specific assembly and distribution. In a large-scale, forward genetic screen, we have identified a mutation termed air traffic controller (atc) that causes T-bar-like protein aggregates to form abnormally in motoneuron axons. This mutation disrupts a gene that encodes for a serine-arginine protein kinase (SRPK79D). This mutant phenotype is specific to SRPK79D and is not secondary to impaired kinesin-dependent axonal transport. The srpk79D gene is neuronally expressed, and transgenic rescue experiments are consistent with SRPK79D kinase activity being necessary in neurons. The SRPK79D protein colocalizes with the T-bar-associated protein Bruchpilot (Brp) in both the axon and synapse. We propose that SRPK79D is a novel T-bar-associated protein kinase that represses T-bar assembly in peripheral axons, and that SRPK79D-dependent repression must be relieved to facilitate site-specific AZ assembly. Consistent with this model, overexpression of SRPK79D disrupts AZ-specific Brp organization and significantly impairs presynaptic neurotransmitter release. These data identify a novel AZ-associated protein kinase and reveal a new mechanism of negative regulation involved in AZ assembly. This mechanism could contribute to the speed and specificity with which AZs are assembled throughout the nervous system.</p>
},
	keywords = {Animals, Drosophila melanogaster, Drosophila Proteins, Immunohistochemistry, Microscopy, Electron, Transmission, Motor Neurons, Presynaptic Terminals, Protein-Serine-Threonine Kinases, Synaptic Transmission},
	issn = {1545-7885},
	doi = {10.1371/journal.pbio.1000193},
	author = {Johnson, Ervin L and Fetter, Richard D and Davis, Graeme W}
}
