Erratum

The conserved PI3′K/PTEN/Akt signaling pathway regulates both cell size and survival in Drosophila

“…In both experiments, the resulting eyes were smaller in size as compared to wild-type eyes (Figure 6a). Experiments on Dp110 and the pto subunit of PI3'K in Drosophila have clearly demonstrated that PI3'K signaling is required for the regulation of both cell size and number (Leevers et al, 1996;Weinkove et al, 1999). Our results here as well as previously published results (Verdu et al, 1999) have de®ned a role for Dakt1 in the regulation of cell size alone.…”

“…This is in sharp contrast to a variety of mutants tested in our laboratory using similar conditions. It is therefore possible that Dakt1 mutation also has an e ect on cell number as in the case of Dp110 (Leevers et al, 1996;Weinkove et al, 1999). These results are consistent with somatic clonal experiments in the eye using the same Dakt1 allele (Verdu et al, 1999).…”

“…For these experiments, cl-8 cell lines expressing wild-type Dp110 (WT Dp110) (Leevers et al, 1996) under the control of an inducible metallothionein (MT-1) promoter were used. Treatment of these cells with CuSO4 resulted in a 3 ± 5-fold increase in WT-Dp110 protein levels ( Loss of Dp110 activity in larval imaginal discs has been shown to result in the decrease of cell size and number (Leevers et al, 1996;Weinkove et al, 1999). As expression of dominant-negative Dp110 in embryos resulted in a phenotype similar to the loss of Dakt1 activity, we decided to test the role of Dakt1 during larval development.…”

“…Recent studies in Drosophila have implicated a role for an insulin-receptor-substrate (IRS) protein (encoded by the chico gene) and phosphatidylinositol-3-OH kinase (PI3'K) in the regulation of cellular growth (BoÈ hni et al, 1999;Leevers et al, 1996;Weinkove et al, 1999). In chico mutants, all aspects of development are normal except for the diminutive size of homozygous chico¯ies (BoÈ hni et al, 1999;Lehner, 1999).…”

Fibroblast growth factor (FGF) signaling through PI 3-kinase and Akt/PKB is required for embryoid body differentiation

“…Similarity of embryoid bodies and the egg cylinder stage rodent embryo emphasizes the probability that the PI 3-kinase-AKT/ PKB pathway may indeed be important for early (Weinkove et al, 1999) and targeted disruption of the p110 a subunit was lethal to mouse embryos at day 9.5 (Bi et al, 1999). These data lend further support to the importance of PI 3-kinase signaling in embryonic development, nevertheless, the multiple isotypes of these genes will complicate their genetic analysis in mammals.…”