Drosophila KAP interacts with the kinesin II motor subunit KLP64D to assemble chordotonal sensory cilia, but not sperm tails.
BACKGROUND
Kinesin II-mediated anterograde intraflagellar transport (IFT) is essential for the assembly and maintenance of flagella and cilia in various cell types. Kinesin associated protein (KAP) is identified as the non-motor accessory subunit of Kinesin II, but its role in the corresponding motor function is not understood.


RESULTS
We show that mutations in the Drosophila KAP (DmKap) gene could eliminate the sensory cilia as well as the sound-evoked potentials of Johnston's organ (JO) neurons. Ultrastructure analysis of these mutants revealed that the ciliary axonemes are absent. Mutations in Klp64D, which codes for a Kinesin II motor subunit in Drosophila, show similar ciliary defects. All these defects are rescued by exclusive expression of DmKAP and KLP64D/KIF3A in the JO neurons of respective mutants. Furthermore, reduced copy number of the DmKap gene was found to enhance the defects of hypomorphic Klp64D alleles. Unexpectedly, however, both the DmKap and the Klp64D mutant adults produce vigorously motile sperm with normal axonemes.


CONCLUSIONS
KAP plays an essential role in Kinesin II function, which is required for the axoneme growth and maintenance of the cilia in Drosophila type I sensory neurons. However, the flagellar assembly in Drosophila spermatids does not require Kinesin II and is independent of IFT.
Sarpal
Ritu
R
Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India.
Todi
Sokol V
SV
Sivan-Loukianova
Elena
E
Shirolikar
Seema
S
Subramanian
Narayan
N
Raff
Elizabeth C
EC
Erickson
James W
JW
Ray
Krishanu
K
Eberl
Daniel F
DF
D000161:Acoustic Stimulation; D000818:Animals; D001692:Biological Transport; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002923:Cilia / Q000378:metabolism* / Q000648:ultrastructure; D004330:Drosophila; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D005072:Evoked Potentials, Auditory; D005407:Flagella / Q000378:metabolism* / Q000648:ultrastructure; D016547:Kinesins / Q000378:metabolism*; D008297:Male; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D016296:Mutagenesis; D009154:Mutation / Q000235:genetics; D009475:Neurons, Afferent / Q000378:metabolism* / Q000648:ultrastructure; D013094:Spermatozoa / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D019076:Transgenes / Q000235:genetics
D002352:Carrier Proteins; D029721:Drosophila Proteins; C486144:Kap3 protein, Drosophila; C486143:KLP64D protein, Drosophila; D016547:Kinesins