Drosophila extracellular signal-regulated kinase involves the insulin-mediated proliferation of Schneider cells.
The Drosophila insulin pathway is involved in the control of the proliferation and size of the cell. The stimulation of Schneider cells with human insulin has been observed to activate Drosophila extracellular signal regulated kinase (DERK). However, the role of DERK in the regulation of proliferation is unknown. In this study, we have identified a role of DERK in the proliferation of Drosophila Schneider cells. The inhibition of DERK activity by the overexpression of DMKP-3, an ERK-specific mitogen-activated protein kinase (MAPK) phosphatase, inhibited G(1) to S phase cell cycle progression as well as bromodeoxyuridine (BrdU) incorporation, which were previously increased by human insulin. However, DMKP-3 overexpression did not significantly reduce cell size that was also enlarged by insulin treatment, which suggests the specificity of the ERK pathway in proliferation but not for cell size. G1 to S phase cell cycle progression and BrdU incorporation were also reduced by catalytically inactive DMKP-3 mutant, and they may be acquired by the trapping of DERK into cytosol. The depletion of DERK or DMKP-3 by inhibitory double-stranded RNA decreased and increased BrdU incorporation, respectively. Thus, we propose that DERK is involved in the proliferation of Schneider cells via the insulin pathway.
Kwon
Hyung-Bae
HB
Department of Biotechnology, Yonsei University College of Engineering, 134 Shinchon-dong, Seodaemun-gu, Korea.
Kim
Sun-Hong
SH
Kim
Sung-Eun
SE
Jang
In-Hwan
IH
Ahn
Yongho
Y
Lee
Won-Jae
WJ
Choi
Kang-Yell
KY
D000818:Animals; D001483:Base Sequence; D002453:Cell Cycle / Q000502:physiology; D002455:Cell Division / Q000502:physiology*; D017931:DNA Primers; D004330:Drosophila; D006801:Humans; D007328:Insulin / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*
D017931:DNA Primers; D007328:Insulin; D020928:Mitogen-Activated Protein Kinases