Drosophila TRPN(=NOMPC) channel localizes to the distal end of mechanosensory cilia.
BACKGROUND
A TRPN channel protein is essential for sensory transduction in insect mechanosensory neurons and in vertebrate hair cells. The Drosophila TRPN homolog, NOMPC, is required to generate mechanoreceptor potentials and currents in tactile bristles. NOMPC is also required, together with a TRPV channel, for transduction by chordotonal neurons of the fly's antennal ear, but the TRPN or TRPV channels have distinct roles in transduction and in regulating active antennal mechanics. The evidence suggests that NOMPC is a primary mechanotransducer channel, but its subcellular location-key for understanding its exact role in transduction-has not yet been established.


RESULTS
Here, by immunostaining, we locate NOMPC at the tips of mechanosensory cilia in both external and chordotonal sensory neurons, as predicted for a mechanotransducer channel. In chordotonal neurons, the TRPN and TRPV channels are respectively segregated into distal and proximal ciliary zones. This zonal separation is demarcated by and requires the ciliary dilation, an intraciliary assembly of intraflagellar transport (IFT) proteins.


CONCLUSIONS
Our results provide a strong evidence for NOMPC as a primary transduction channel in Drosophila mechansensory organs. The data also reveals a structural basis for the model of auditory chordotonal transduction in which the TRPN and TRPV channels play sequential roles in generating and amplifying the receptor potential, but have opposing roles in regulating active ciliary motility.
Lee
Jeongmi
J
Department of Life Sciences, University of Seoul, Seoul, Korea.
Moon
Sungjin
S
Cha
Yoonseok
Y
Chung
Yun Doo
YD
D000818:Animals; D030801:Animals, Genetically Modified; D002923:Cilia / Q000378:metabolism*; D004330:Drosophila / Q000378:metabolism*; D029721:Drosophila Proteins / Q000378:metabolism*; D007473:Ion Channels / Q000378:metabolism*; D040542:Mechanotransduction, Cellular; D018613:Microscopy, Confocal; D050051:Transient Receptor Potential Channels
D029721:Drosophila Proteins; D007473:Ion Channels; C405783:NOMPC protein, Drosophila; D050051:Transient Receptor Potential Channels