KinasePhos 3.0:Redesign and Expansion of the Prediction on Kinase-specific Phosphorylation Sites

The purpose of this work is to enhance KinasePhos,a machine learning-based kinasespecific phosphorylation site prediction tool.Experimentally verified kinase-specific phosphorylation data were collected from PhosphoSitePlus,UniProtKB,the GPS 5.0,and Phospho.ELM.In total,41,421 experimentally verified kinase-specific phosphorylation sites were identified.A total of 1380 unique kinases were identified,including 753 with existing classification information from KinBase and the remaining 627 annotated by building a phylogenetic tree.Based on this kinase classification,a total of 771 predictive models were built at the individual,family,and group levels,using at least 15 experimentally verified substrate sites in positive training datasets.The improved models demonstrated their effectiveness compared with other prediction tools.For example,the prediction of sites phosphorylated by the protein kinase B,casein kinase 2,and protein kinase A families had accuracies of 94.5%,92.5%,and 90.0%,respectively.The average prediction accuracy for all 771 models was 87.2%.For enhancing interpretability,the SHapley Additive exPlanations(SHAP)method was employed to assess feature importance.The web interface of KinasePhos 3.0 has been redesigned to provide comprehensive annotations of kinase-specific phosphorylation sites on multiple proteins.Additionally,considering the large scale of phosphoproteomic data,a downloadable prediction tool is available at https://awi.cuhk.edu.cn/KinasePhos/download.html or https://github.com/tom-209/KinasePhos-3.0-executable-file.

SuccSite:Incorporating Amino Acid Composition and Informative k-spaced Amino Acid Pairs to Identify Protein Succinylation Sites

Protein succinylation is a biochemical reaction in which a succinyl group(-CO-CH2-CH2-CO-)is attached to the lysine residue of a protein molecule.Lysine succinylation plays important regulatory roles in living cells.However,studies in this field are limited by the difficulty in experimentally identifying the substrate site specificity of lysine succinylation.To facilitate this process,several tools have been proposed for the computational identification of succinylated lysine sites.In this study,we developed an approach to investigate the substrate specificity of lysine succinylated sites based on amino acid composition.Using experimentally verified lysine succinylated sites collected from public resources,the significant differences in position-specific amino acid composition between succinylated and non-succinylated sites were represented using the Two Sample Logo program.These findings enabled the adoption of an effective machine learning method,support vector machine,to train a predictive model with not only the amino acid composition,but also the composition of k-spaced amino acid pairs.After the selection of the best model using a ten-fold crossvalidation approach,the selected model significantly outperformed existing tools based on an independent dataset manually extracted from published research articles.Finally,the selected model was used to develop a web-based tool,SuccSite,to aid the study of protein succinylation.Two proteins were used as case studies on the website to demonstrate the effective prediction of succinylation sites.We will regularly update SuccSite by integrating more experimental datasets.SuccSite is freely accessible at http://csb.cse.yzu.edu.tw/SuccSite/.