Erin Jonasson, Valentina Rossio, Riko Hatakeyama (Brandeis Univ.) Mitsuhiro Abe, Yoshikazu Ohya (Univ. Tokyo) Satoshi Yoshida (GIAR and IMCR, Gunma Univ.)

About

Budding yeast Rho1 guanosine triphosphatase (GTPase) plays an essential role in polarized cell growth by regulating cell wall glucan synthesis and actin organization. Upon cell wall damage, Rho1 blocks polarized cell growth and repairs the wounds by activating the cell wall integrity (CWI) Pkc1–mitogen-activated protein kinase (MAPK) pathway. A fundamental question is how active Rho1 promotes distinct signaling outputs under different conditions. Here we identified the Zds1/Zds2–protein phosphatase 2A^Cdc55 (PP2A^Cdc55) complex as a novel Rho1 effector that regulates Rho1 signaling specificity. Zds1/Zds2–PP2A^Cdc55 promotes polarized growth and cell wall synthesis by inhibiting Rho1 GTPase-activating protein (GAP) Lrg1 but inhibits CWI pathway by stabilizing another Rho1 GAP, Sac7, suggesting that active Rho1 is biased toward cell growth over stress response. Conversely, upon cell wall damage, Pkc1–Mpk1 activity inhibits cortical PP2A^Cdc55, ensuring that Rho1 preferentially activates the CWI pathway for cell wall repair. We propose that PP2A^Cdc55 specifies Rho1 signaling output and that reciprocal antagonism between Rho1–PP2A^Cdc55 and Rho1–Pkc1 explains how only one signaling pathway is robustly activated at a time.

Paper information

"Zds1/Zds2-PP2ACdc55 complex specifies signaling output from Rho1 GTPase"
Erin Jonasson, Valentina Rossio, Riko Hatakeyama, Mitsuhiro Abe, Yoshikazu Ohya, Satoshi Yoshida*
The Journal of Cell Biology (2016) Vol 212. No. 1:51-61.

Online URL

http://jcb.rupress.org/content/212/1/51.abstract

Lab HP

http://www.giar.gunma-u.ac.jp/program/program_st/