Protein kinase D regulates several aspects of development in Drosophila melanogaster.
BACKGROUND
Protein Kinase D (PKD) is an effector of diacylglycerol-regulated signaling pathways. Three isoforms are known in mammals that have been linked to diverse cellular functions including regulation of cell proliferation, differentiation, motility and secretory transport from the trans-Golgi network to the plasma membrane. In Drosophila, there is a single PKD orthologue, whose broad expression implicates a more general role in development.


RESULTS
We have employed tissue specific overexpression of various PKD variants as well as tissue specific RNAi, in order to investigate the function of the PKD gene in Drosophila. Apart from a wild type (WT), a kinase dead (kd) and constitutively active (SE) Drosophila PKD variant, we also analyzed two human isoforms hPKD2 and hPKD3 for their capacity to substitute PKD activity in the fly. Overexpression of either WT or kd-PKD variants affected primarily wing vein development. However, overexpression of SE-PKD and PKD RNAi was deleterious. We observed tissue loss, wing defects and degeneration of the retina. The latter phenotype conforms to a role of PKD in the regulation of cytoskeletal dynamics. Strongest phenotypes were larval to pupal lethality. RNAi induced phenotypes could be rescued by a concurrent overexpression of Drosophila wild type PKD or either human isoform hPKD2 and hPKD3.


CONCLUSIONS
Our data confirm the hypothesis that Drosophila PKD is a multifunctional kinase involved in diverse processes such as regulation of the cytoskeleton, cell proliferation and death as well as differentiation of various fly tissues.
Maier
Dieter
D
Universität Hohenheim, Institut für Genetik (240), Stuttgart, Germany. maierdie@uni-hohenheim.de <maierdie@uni-hohenheim.de>
Nagel
Anja C
AC
Gloc
Helena
H
Hausser
Angelika
A
Kugler
Sabrina J
SJ
Wech
Irmgard
I
Preiss
Anette
A
D000375:Aging / Q000502:physiology; D000818:Animals; D030801:Animals, Genetically Modified; D002460:Cell Line; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000033:anatomy & histology / Q000201:enzymology* / Q000254:growth & development*; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins / Q000235:genetics / Q000378:metabolism; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D007814:Larva / Q000033:anatomy & histology / Q000502:physiology; D008027:Light; D010641:Phenotype; D017956:Photoreceptor Cells, Invertebrate / Q000378:metabolism / Q000473:pathology; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D014921:Wings, Animal / Q000033:anatomy & histology / Q000254:growth & development
C111891:DIAP1 protein, Drosophila; D029721:Drosophila Proteins; D051034:Inhibitor of Apoptosis Proteins; D007527:Isoenzymes; D011993:Recombinant Fusion Proteins; C089212:protein kinase D; D011493:Protein Kinase C