Ca2+-dependent successive phosphorylation of vacuolar transporter MTP8 by CBL2/3-CIPK3/9/26 and CPK5 contributes to manganese homeostasis in Arabidopsis

编号 040032804

推送时间 20220131

研究领域 森林培育 

年份 2022 

类型 期刊 

语种 英语

标题 Ca2+-dependent successive phosphorylation of vacuolar transporter MTP8 by CBL2/3-CIPK3/9/26 and CPK5 contributes to manganese homeostasis in Arabidopsis

来源期刊 Molecular Plant

期 第328期

发表时间 20211126

关键词 Manganese;  Ca2+;  Calcineurin B-like proteins (CBLs);  CBL18
interacting protein kinases (CIPKs);  Mn transporter MTP8;  Calcium19 dependent protein kinases (CPKs); 

摘要 Manganese (Mn) is an essential micronutrient for all living organisms. However, excess supply of Mn as occurring in acid or waterlogged soils has toxic effects on plant physiology and development. Although a variety of Mn transporter families has been characterized, our understanding of how these transporters are regulated to uphold and adjust Mn homeostasis in plants remains rudimentary. Here, we identify two calcineurin-B-like proteins, CBL2/3, and their interacting kinases, CIPK3/9/26, as key regulators for plant Mn homeostasis. We found that Arabidopsis mutants lacking CBL2 and 3 or their interacting protein kinases CIPK3/9/26 exhibit remarkable high-Mn tolerance. Intriguingly, CIPK3/9/26 interact with and phosphorylate the tonoplast-localized Mn and iron (Fe) transporter MTP8 primarily at Ser35, which is conserved among MTP8 proteins from various species. Mn transport complementation assays in yeast combined with multiple physiological assays indicate that CBL-CIPK-mediated phosphorylation of MTP8 negatively regulates its transport activity from the cytoplasm to the vacuole. Moreover, we report that sequential phosphorylation of MTP8 initially at Ser31/32 by the calcium-dependent protein kinases CPK5 and subsequently by CIPK26 at Ser35 provides an activation/deactivation fine-tuning mechanism for differential Mn transport regulation. Collectively, our studies define a two-tiered calcium-controlled mechanism for dynamically orchestrating Mn homeostasis under conditions of fluctuating Mn supply.

服务人员 孙小满

服务院士 尹伟伦

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