Chawla Srishti, Kundu Debasree, Randhawa Anmoldeep, Mondal Alok K
CSIR-Institute of Microbial Technology, Chandigarh 160036, India.
School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067.
Gene. 2017 Mar 30;606:1-9. doi: 10.1016/j.gene.2016.12.022. Epub 2016 Dec 24.
The highly conserved family of Phosphoprotein phosphatases (PPP) regulates several major physiological processes in yeast. However, very little is known about the PPP orthologs from the yeast species inhabiting extreme environmental niches. In the present study we have identified DhSIT4, a member of PPP6 class of serine threonine phosphatases from the halotolerant yeast Debaryomyces hansenii. Deletion of DhSIT4 in D. hansenii was not lethal but the mutant exhibited reduced growth due to its effect on the cell cycle. The knock out mutant Dhsit4Δ showed sensitivity towards Li, Na and cell wall damaging agents. The expression of DhSit4p rescued salt, caffeine and calcofluor white sensitivity of Dhmpk1Δ strain and thereby indicating a genetic interaction of this phosphatase with the cell wall integrity pathway in this species. Our study also demonstrated the antagonistic roles of DhSit4p and DhPpz1p in maintaining the cell cycle and ion homeostasis in D. hansenii.
磷酸蛋白磷酸酶（PPP）的高度保守家族调节酵母中的几个主要生理过程。然而，对于栖息在极端环境生态位中的酵母物种的PPP直系同源物知之甚少。在本研究中，我们鉴定了DhSIT4，它是来自耐盐酵母汉逊德巴利酵母的丝氨酸苏氨酸磷酸酶PPP6类的成员。在汉逊德巴利酵母中缺失DhSIT4并非致命，但突变体由于其对细胞周期的影响而生长减缓。敲除突变体Dhsit4Δ对锂、钠和细胞壁损伤剂敏感。DhSit4p的表达挽救了Dhmpk1Δ菌株对盐、咖啡因和钙荧光白的敏感性，从而表明该磷酸酶与该物种的细胞壁完整性途径存在遗传相互作用。我们的研究还证明了DhSit4p和DhPpz1p在维持汉逊德巴利酵母的细胞周期和离子稳态中的拮抗作用。
