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bioRxiv · 10.1101/2022.02.14.480437

Insulin/IGF Signaling Regulates Presynaptic Glutamate Release in Aversive Olfactory Learning

Bargmann, C. I.·Cheng, D.·Lee, J.·Ebert, M.·Brown, M.·Tomioka, M.·Iino, Y.
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Abstract

Information flow through neural circuits is continuously modified by context-dependent learning. In the nematode Caenorhabditis elegans, pairing specific odors with food deprivation results in aversion to the odor. Here we identify cell-specific mechanisms of insulin/IGF receptor signaling that integrate sensory information with food context during aversive olfactory learning. Using a conditional allele of the insulin/IGF receptor DAF-2, we show that aversive learning to butanone, an odor sensed only by the AWCON olfactory neuron, requires DAF-2 in AWCON. Learning requires an axonally-localized DAF-2c isoform and the insulin receptor substrate (IRS) protein IST-1, but is partly independent of the FoxO transcription factor DAF-16. Upon food deprivation, the unconditioned stimulus for learning, DAF-2 expression increases post-transcriptionally through an insulin- and ist-1-dependent process. Aversive learning suppresses odor-regulated glutamate release from AWCON in wild-type animals but not in ist-1 mutants, suggesting that localized insulin signaling drives presynaptic depression to generate an aversive memory.

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Bargmann, C. I., Cheng, D., Lee, J., Ebert, M., Brown, M., Tomioka, M., Iino, Y.. 2022-02-15. Insulin/IGF Signaling Regulates Presynaptic Glutamate Release in Aversive Olfactory Learning. https://doi.org/10.1101/2022.02.14.480437

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