PT  - JOURNAL ARTICLE
AU  - Rafael Lucena
AU  - Maria Alcaide-Gavilán
AU  - Katherine Schubert
AU  - Maybo He
AU  - Matthew Domnauer
AU  - Catherine Marquer
AU  - Douglas R. Kellogg
TI  - Cell size and growth rate are modulated by TORC2-dependent signals
AID  - 10.1101/188698
DP  - 2017 Jan 01
TA  - bioRxiv
PG  - 188698
4099  - http://biorxiv.org/content/early/2017/09/14/188698.short
4100  - http://biorxiv.org/content/early/2017/09/14/188698.full
AB  - The size of all cells, from bacteria to vertebrates, is proportional to the growth rate set by nutrient availability, but the underlying mechanisms are unknown. Here, we show that nutrients modulate TORC2 signaling, and that cell size is proportional to TORC2 signaling in budding yeast. The TORC2 network controls production of ceramide lipids, which play roles in signaling. We discovered that ceramide-dependent signals control both growth rate and cell size. Thus, cells that can not make ceramides fail to modulate their growth rate or size in response to changes in nutrients. PP2A associated with the Rts1 regulatory subunit (PP2ARts1) is embedded in a feedback loop that controls TORC2 signaling and plays an important role in mechanisms that modulate TORC2 signaling in response to nutrients. Together, the data suggest a model in which growth rate and cell size are mechanistically linked by ceramide-dependent signals arising from the TORC2 network.