Regulation of synaptic transmission at the Caenorhabditis elegans M4 neuromuscular junction by an antagonistic relationship between two calcium channels.
In wild-type Caenorhabditis elegans, the synapse from motor neuron M4 to pharyngeal terminal bulb (TB) muscles is silent, and the muscles are instead excited by gap junction connections from adjacent muscles. An eat-5 innexin mutant lacking this electrical connection has few TB contractions and is unable to grow well on certain foods. We showed previously that this defect can be overcome by activation of the M4 → TB synapse. To identify genes that negatively regulate synaptic transmission, we isolated new suppressors of eat-5. To our surprise, these suppressors included null mutations in NPQR-type calcium channel subunit genes unc-2 and unc-36. Our results are consistent with the hypothesis that Ca(2+) entry through the NPQR-type channel inhibits synaptic transmission by activating the calcium-activated K(+) channel SLO-1, thus antagonizing the EGL-19 L-type calcium channel.
Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9148.
Mark
M
Steciuk
Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia 23298-0551.
Mi
M
Cheong
Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia 23298-0551.
Christopher
C
Waite
Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, Virginia 23298-0614.
Young-Jai
YJ
You
Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia 23298-0551 lavery3@vcu.edu.
Leon
L
Avery
D000465:Algorithms; D000818:Animals; D030801:Animals, Genetically Modified / Q000235:genetics; D017173:Caenorhabditis elegans / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017630:Connexins / Q000235:genetics / Q000378:metabolism; D016678:Genome; D051036:Large-Conductance Calcium-Activated Potassium Channels / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D009124:Muscle Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D059645:Mutation Rate; D009469:Neuromuscular Junction / Q000378:metabolism*; D009435:Synaptic Transmission / Q000235:genetics / Q000502:physiology*
D029742:Caenorhabditis elegans Proteins; D015220:Calcium Channels; D017630:Connexins; C109164:Egl-19 protein, C elegans; D051036:Large-Conductance Calcium-Activated Potassium Channels; D008565:Membrane Proteins; D009124:Muscle Proteins; C585116:UNC-36 protein, C elegans; C100765:eat-5 protein, C elegans; C494845:slo-1 protein, C elegans; C093204:unc-2 protein, C elegans; D002118:Calcium
BK channel; behavior; calcium channels; feeding; synaptic transmission