Department of Chemistry, University of Louisiana at Lafayette, Lafayette, LA, 70504, USA.
State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Rd, Beijing, 100101, China.
Appl Biochem Biotechnol. 2021 Mar;193(3):687-716. doi: 10.1007/s12010-020-03435-2. Epub 2020 Nov 6.
Cyanobacterium Synechocystis sp. PCC 6803, a popular model organism for researches in photosynthesis and biofuel production, contains plant-like photosynthetic machineries which significantly contribute to global carbon fixation. There are 12 eukaryotic-type Ser/Thr kinases (SpkA-L) and 49 His kinases (Hik1-49) of two-component systems in the genome of Synechocystis sp. PCC 6803. They are the key regulators in sensing and transmitting stimuli including light- and glucose-mediate signal transduction. Proteomic studies were able to identify all the kinases. The majority of kinases no matter whether they have a predicted transmembrane domain were identified in the membrane fractions. Six Ser/Thr kinases (SpkA-D, F and G) and ten His kinases (Hik4, 12, 14, 21, 26-27, 29, 36, 43, and 46) were identified to have one or more of the three types of post-translational modifications: phosphorylation, acetylation, and thiol oxidation. Interestingly, SpkG has the phosphorylatable threonine residue that was aligned with the phosphorylated threonine residue in the activation loop of human CDK7, demonstrating conserved phosphorylation between cyanobacterial and human kinases. Transcriptomics and proteomics revealed differential expression of the kinases in heterotrophic and photoheterotrophic compared with photoautotrophic conditions, indicating their roles in regulating the growth modes of cyanobacteria. In summary, this review focuses on the discussions on post-transcriptional modifications, transcriptomic, and proteomic studies of Ser/Thr and His kinases. This together with our published review in 2019 present a complete story of an overview of sequences, domain architectures, and biochemical and physiological functions of cyanobacterial kinases with adequate details in the context of high throughput systems. We also emphasize the importance of discovering upstream molecules and substrates to understand the exact functions of the kinases in vivo. As an attempt, a model is proposed in which Hik31, His33, Sll1334, and IcfG are hypothesized to be critical for switching between autotrophic and heterotrophic modes based on the results from the phenotypes of the gene knockout strains combined with their post-translational modifications, and gene expression profiles.
集胞藻 PCC 6803 是一种常用于光合作用和生物燃料生产研究的模式生物，它含有植物样光合作用机器，对全球碳固定有重要贡献。集胞藻 PCC 6803 的基因组中含有 12 种真核型丝氨酸/苏氨酸激酶（SpkA-L）和 49 种组氨酸激酶（Hik1-49）的双组分系统。它们是感应和传递刺激的关键调节剂，包括光和葡萄糖介导的信号转导。蛋白质组学研究能够鉴定所有的激酶。大多数激酶，无论它们是否具有预测的跨膜结构域，都在膜部分被鉴定出来。6 种丝氨酸/苏氨酸激酶（SpkA-D、F 和 G）和 10 种组氨酸激酶（Hik4、12、14、21、26-27、29、36、43 和 46）被鉴定出具有一种或多种三种类型的翻译后修饰：磷酸化、乙酰化和硫醇氧化。有趣的是，SpkG 具有可磷酸化的苏氨酸残基，与人类 CDK7 的激活环中的磷酸化苏氨酸残基对齐，表明蓝细菌和人类激酶之间存在保守的磷酸化。转录组学和蛋白质组学研究表明，与自养相比，异养和光异养条件下激酶的表达不同，这表明它们在调节蓝藻的生长模式方面的作用。总之，本综述重点讨论了丝氨酸/苏氨酸和组氨酸激酶的转录后修饰、转录组学和蛋白质组学研究。这与我们 2019 年发表的综述一起，完整地介绍了蓝细菌激酶的序列、结构域架构以及生化和生理功能的概述，提供了足够详细的高通量系统背景信息。我们还强调了发现上游分子和底物以了解激酶在体内的确切功能的重要性。作为一种尝试，提出了一个模型，假设 Hik31、His33、Sll1334 和 IcfG 基于基因敲除菌株的表型与它们的翻译后修饰和基因表达谱相结合的结果，对于在自养和异养模式之间切换是至关重要的。
