TY - JOUR
T1 - The phosphatase subunit Tap42 functions independently of target of rapamycin to regulate cell division and survival in drosophila
AU - Cygnar, Katherine D.
AU - Gao, Xinsheng
AU - Pan, Duojia
AU - Neufeld, Thomas P.
PY - 2005/6
Y1 - 2005/6
N2 - The protein phosphatase 2A (PP2A) regulatory subunit Tap42 is essential for target of rapamycin (TOR)-mediated signaling in yeast, but its role in higher eukaryotes has not been established. Here we show that Tap42 does not contribute significantly to TOR signaling in Drosophila, as disruption of the Tap42 gene does not cause defects in cell growth, metabolism, or S6-kinase activity characteristic of TOR inactivation. In addition, Tap42 is not required for increased cell growth in response to activation of TOR signaling. Instead, we find that Tap42 mutations cause disorganization of spindle microtubules in larval neuroblasts, leading to a preanaphase mitotic arrest in these cells. Loss of Tap42 ultimately results in increased JNK signaling, caspase activation, and cell death. These phenotypes are associated with increased accumulation and nuclear localization of PP2A in Tap42 mutant cells. Our results demonstrate that the role of Tap42 in TOR signaling has not been conserved in higher eukaryotes, indicating fundamental differences in the mechanisms of TOR signaling between yeast and higher eukaryotes.
AB - The protein phosphatase 2A (PP2A) regulatory subunit Tap42 is essential for target of rapamycin (TOR)-mediated signaling in yeast, but its role in higher eukaryotes has not been established. Here we show that Tap42 does not contribute significantly to TOR signaling in Drosophila, as disruption of the Tap42 gene does not cause defects in cell growth, metabolism, or S6-kinase activity characteristic of TOR inactivation. In addition, Tap42 is not required for increased cell growth in response to activation of TOR signaling. Instead, we find that Tap42 mutations cause disorganization of spindle microtubules in larval neuroblasts, leading to a preanaphase mitotic arrest in these cells. Loss of Tap42 ultimately results in increased JNK signaling, caspase activation, and cell death. These phenotypes are associated with increased accumulation and nuclear localization of PP2A in Tap42 mutant cells. Our results demonstrate that the role of Tap42 in TOR signaling has not been conserved in higher eukaryotes, indicating fundamental differences in the mechanisms of TOR signaling between yeast and higher eukaryotes.
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U2 - 10.1534/genetics.104.039909
DO - 10.1534/genetics.104.039909
M3 - Article
C2 - 15802506
AN - SCOPUS:22144461779
SN - 0016-6731
VL - 170
SP - 733
EP - 740
JO - Genetics
JF - Genetics
IS - 2
ER -