Multiple TORC1-associated proteins regulate nitrogen starvation-dependent cellular differentiation in Saccharomyces cerevisiae
Authors: Benjamin P Tu
Sunil Laxman
Journal: PLoS ONE (2011)
Discipline: Multidisciplinary
Keywords: yeast; Saccharomyces cerevisiae; filamentous growth; TORC1; nitrogen starvation
Affiliations: Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America. 

Abstract:  Background: The budding yeast Saccharomyces cerevisiae undergoes differentiation into filamentous-like forms and invades the growth medium as a foraging response to nutrient and environmental stresses. These developmental responses are under the downstream control of effectors regulated by the cAMP/PKA and MAPK pathways. However, the upstream sensors and signals that induce filamentous growth through these signaling pathways are not fully understood. Herein, through a biochemical purification of the yeast TORC1 (Target of Rapamycin Complex 1), we identify several proteins implicated in yeast filamentous growth that directly associate with the TORC1 and investigate their roles in nitrogen starvation-dependent or independent differentiation in yeast. Methodology: We isolated the endogenous TORC1 by purifying tagged, endogenous Kog1p, and identified associated proteins by mass spectrometry. We established invasive and pseudohyphal growth conditions in two S. cerevisiae genetic backgrounds (Œ£1278b and CEN.PK). Using wild type and mutant strains from these genetic backgrounds, we investigated the roles of TORC1 and associated proteins in nitrogen starvation-dependent diploid pseudohyphal growth as well as nitrogen starvation-independent haploid invasive growth. Conclusions: We show that several proteins identified as associated with the TORC1 are important for nitrogen starvation-dependent diploid pseudohyphal growth. In contrast, invasive growth due to other nutritional stresses was generally not affected in mutant strains of these TORC1-associated proteins. Our studies suggest a role for TORC1 in yeast differentiation upon nitrogen starvation. Our studies also suggest the CEN.PK strain background of S. cerevisiae may be particularly useful for investigations of nitrogen starvation-induced diploid pseudohyphal growth. 

Retracted: No

PubPeer comments:
 This article has been retracted at the request of the Editor-in-Chief. The Western blots from Figures 3A and D are similar to Western blots from Figures 3A and D of the article published by Yongfang Wang, Lianhong Xu and Lixin Jiang in Biochemical and Biophysical Research Communications (BBRC) 458 (2015) 714u2013719 In addition, a significant amount of textual overlap has been noticed between this article and the articles published by BBRC 458 (2015) 714u2013719 and PLoS ONE 9 (10) (2014) e109734 One of the conditions of submission of a paper for publication is that authors declare explicitly that their work is original and has not appeared in a publication elsewhere. Re-use of any data should be appropriately cited. As such this article represents a severe abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process. ,