Fission yeast homologue of Tip41-like proteins regulates type 2A phosphatases and responses to nitrogen sources

Abstract

A fission yeast (Schizosaccharomyces pombe) gene encoding a member of the TIP41-like protein family was identified and characterized. Deletion of the fission yeast tip41 gene leads to slower growth when ammonium chloride is the nitrogen source, but the growth rate is not affected when adenine is the nitrogen source. The tip41 mutant cells also enter the G1 phase of the cell cycle earlier than wild-type cells in response to nitrogen starvation. Overexpression of tip41(+) causes cell death, spherical cell morphology and blocks the shift to G1 phase upon nitrogen starvation. Overexpression of tip41(+) increases the activity of type 2A phosphatase. In a ppa2 deletion strain with reduced PP2A activity, overexpression of tip41(+) no longer blocks the shift to G1 upon nitrogen starvation. These results suggest that fission yeast Tip41 plays a role in cellular responses to nitrogen nutrient conditions at least partly through regulation of type 2A phosphatase activity.

Characterization of cytopathic factors through genome-wide analysis of the Zika viral proteins in fission yeast

“…4 A, b, Right), suggesting the action of NS4A behaved at least in part like that of Tip41 protein. This premise is supported by the fact that Tip41 is a negative regulator of Tor1 (57,58). Additional experiments are needed to verify this possibility.…”

“…Our results described here are largely in agreement with that report. In addition, we showed that NS4A confers its cytopathic effects specifically through Tor1 and Tip41, which are the human equivalents of Tsc1 and Tip41 proteins (58,78). It would be interesting to examine further whether the other six ZIKV proteins exert an effect similar to that of NS4A.…”

“…A wild-type fission yeast SP223 strain (h-, ade6-216, leu1-32, ura4-294) was used in this study (36,41). The Tor1-deletion mutant strain MA99 (h-, tor1::ura4+ leu1-32, ura4-Δ18, ade6-M216) and the Tip41-deletion mutant strain I3-24 (h − , vsp24::ura4+; leu1-32, ura4-294, ade6-M216) were described previously (55,58). Standard yeast extract with supplements (YES) complete medium or minimal EMM selective medium supplemented with adenine, uracil, leucine, or thiamine (20 μM) was used to grow fission yeast cells or to select for plasmid-carrying cells, respectively.…”

“…4 A, a, Left and 4 D, Middle). The Tip41 protein also is involved in the cellular response to nitrogen starvation, and it negatively regulates the TOR signaling pathway in budding yeast (57,58). Deletion of the Tip41 gene had no clear effect on cell size (Fig.…”

Nitrogen depletion causes up-regulation of glutathione content and γ-glutamyltranspeptidase in Schizosaccharomyces pombe

“…Tor2-depleted fission yeast cells exhibit a phenotype very similar to that of wild-type cells starved for nitrogen, including arrest at the G1 phase of the cell cycle, induction of nitrogen-starvation-specific genes, and entrance into the sexual development pathway, which is in contrast to the failure of tor1 mutants to initiate sexual development or arrest in G1 under nitrogen starvation (Matsuo et al, 2007;Weisman et al, 2007). The fission yeast Tip41, a regulator of TAP42 required for Tor regulation, also plays a partial role in cellular responses to nitrogen nutrient conditions through regulation of type 2A phosphatase activity (Fenyvuesvolgyi et al, 2005). The tip41 mutant cells also enter the G1 phase earlier than wild-type cells in response to nitrogen starvation, while overexpression of tip41(+) causes cell death, spherical cell morphology and blocks the shift to the G1 phase upon nitrogen starvation (Fenyvuesvolgyi et al, 2005).…”