Kinesin-2 transports Orco into the olfactory cilium of Drosophila melanogaster at specific developmental stages

PLoS Genet. 2021 Aug 19;17(8):e1009752. doi: 10.1371/journal.pgen.1009752. eCollection 2021 Aug.

Abstract

The cilium, the sensing centre for the cell, displays an extensive repertoire of receptors for various cell signalling processes. The dynamic nature of ciliary signalling indicates that the ciliary entry of receptors and associated proteins must be regulated and conditional. To understand this process, we studied the ciliary localisation of the odour-receptor coreceptor (Orco), a seven-pass transmembrane protein essential for insect olfaction. Little is known about when and how Orco gets into the cilia. Here, using Drosophila melanogaster, we show that the bulk of Orco selectively enters the cilia on adult olfactory sensory neurons in two discrete, one-hour intervals after eclosion. A conditional loss of heterotrimeric kinesin-2 during this period reduces the electrophysiological response to odours and affects olfactory behaviour. We further show that Orco binds to the C-terminal tail fragments of the heterotrimeric kinesin-2 motor, which is required to transfer Orco from the ciliary base to the outer segment and maintain within an approximately four-micron stretch at the distal portion of the ciliary outer-segment. The Orco transport was not affected by the loss of critical intraflagellar transport components, IFT172/Oseg2 and IFT88/NompB, respectively, during the adult stage. These results highlight a novel developmental regulation of seven-pass transmembrane receptor transport into the cilia and indicate that ciliary signalling is both developmentally and temporally regulated.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biological Transport
  • Carrier Proteins / metabolism
  • Cilia / genetics
  • Cilia / metabolism*
  • Drosophila Proteins / metabolism*
  • Drosophila Proteins / physiology
  • Drosophila melanogaster / metabolism
  • Kinesins / metabolism*
  • Kinesins / physiology
  • Olfactory Bulb / metabolism
  • Olfactory Receptor Neurons / metabolism
  • Protein Transport
  • Receptors, Odorant / metabolism*
  • Receptors, Odorant / physiology
  • Smell

Substances

  • Carrier Proteins
  • Drosophila Proteins
  • Orco protein, Drosophila
  • Receptors, Odorant
  • kinesin 2 protein, Drosophila
  • Kinesins

Grants and funding

The study was funded by the Department of Atomic Energy, Government of India, TIFR DAE grant nos. 12-R&D-TFR-5.10-100 and RIT4003 (Biol, Chem, Phys & Material Sc.) to K. R. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.