Chakraborty Shuvechha, Mahin Althaf, Shivamurthy Prathik Basthikoppa, Ahmed Mukhtar, Gopalakrishnan Athira Perunelly, John Levin, Varghese Susmi, Ramesh Poornima, Raju Rajesh
Centre for Integrative Omics Data Science (CIODS), Yenepoya (Deemed to be University), Mangalore, Karnataka, 575018, India.
Department of Zoology, College of Science, King Saud University, P. O. Box 2455, Riyadh, Kingdom of Saudi Arabia, 11451.
Biochem Biophys Rep. 2025 Aug 5;43:102196. doi: 10.1016/j.bbrep.2025.102196. eCollection 2025 Sep.
The GFPT2 protein, also known as glutamine-fructose-6-phosphate aminotransferase 2, regulates glucose flux through the hexosamine biosynthesis pathway (HBP). It is primarily expressed in the spinal cord and central nervous system and is notably abundant in various cancers while being dysregulated in diabetes. Despite its significant role in critical diseases, the phospho-regulatory mechanisms governing GFPT2 function remain largely unexplored. To investigate the phospho-signaling networks of GFPT2, an analysis of the global phosphoproteomes examining GFPT2 phosphorylation sites (PS) across diverse experimental conditions was conducted. By compiling 448 qualitative and 74 quantitative differential cellular phosphoproteome datasets, a key phosphorylation site, S244, was identified in GFPT2, appearing in approximately 81 % of these datasets. Surprisingly, the functional significance of this phosphosite had not been studied or reported. A targeted strategy was employed to identify PS in proteins whose expression coregulated with the primary GFPT2 phosphorylation site. Subsequent functional analysis of these coregulated proteins revealed associations with neuronal disorders. Classification of coregulated phosphosites in proteins as known and predicted GFPT2 interactors, kinases, and substrates enabled the inference of regulatory phospho-signaling dynamics associated with GFPT2. Further, GFPT2 phosphorylation at S244 was identified to be regulated by two potential upstream kinases CHEK1 and PKN1, that showed positive coregulation with kinase activity increasing phosphosites. These findings provide novel insights into the cellular phospho-signaling networks associated with GFPT2, offering potential implications for therapeutic interventions.
GFPT2蛋白，也称为谷氨酰胺-果糖-6-磷酸氨基转移酶2，通过己糖胺生物合成途径（HBP）调节葡萄糖通量。它主要在脊髓和中枢神经系统中表达，在各种癌症中显著丰富，而在糖尿病中失调。尽管它在关键疾病中发挥着重要作用，但控制GFPT2功能的磷酸化调节机制在很大程度上仍未得到探索。为了研究GFPT2的磷酸化信号网络，对在不同实验条件下检测GFPT2磷酸化位点（PS）的全局磷酸化蛋白质组进行了分析。通过汇编448个定性和74个定量的差异细胞磷酸化蛋白质组数据集，在GFPT2中鉴定出一个关键的磷酸化位点S244，约81%的这些数据集中出现该位点。令人惊讶的是，这个磷酸化位点的功能意义尚未得到研究或报道。采用靶向策略来鉴定与主要GFPT2磷酸化位点共表达的蛋白质中的PS。随后对这些共调节蛋白质的功能分析揭示了它们与神经元疾病的关联。将蛋白质中共调节的磷酸化位点分类为已知和预测的GFPT2相互作用蛋白、激酶和底物，能够推断与GFPT2相关的调节磷酸化信号动态。此外，已确定S244处的GFPT2磷酸化受两种潜在的上游激酶CHEK1和PKN1调节，这两种激酶与激酶活性呈正共调节，激酶活性增加磷酸化位点。这些发现为与GFPT2相关的细胞磷酸化信号网络提供了新的见解，对治疗干预具有潜在意义。
