Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada.
Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada; Ottawa Institute of Systems Biology, Ottawa, ON K1H 8M5, Canada.
Mol Cell. 2024 May 2;84(9):1802-1810.e4. doi: 10.1016/j.molcel.2024.03.028.
Polyphosphate (polyP) is a chain of inorganic phosphate that is present in all domains of life and affects diverse cellular phenomena, ranging from blood clotting to cancer. A study by Azevedo et al. described a protein modification whereby polyP is attached to lysine residues within polyacidic serine and lysine (PASK) motifs via what the authors claimed to be covalent phosphoramidate bonding. This was based largely on the remarkable ability of the modification to survive extreme denaturing conditions. Our study demonstrates that lysine polyphosphorylation is non-covalent, based on its sensitivity to ionic strength and lysine protonation and absence of phosphoramidate bond formation, as analyzed via P NMR. Ionic interaction with lysine residues alone is sufficient for polyP modification, and we present a new list of non-PASK lysine repeat proteins that undergo polyP modification. This work clarifies the biochemistry of polyP-lysine modification, with important implications for both studying and modulating this phenomenon. This Matters Arising paper is in response to Azevedo et al. (2015), published in Molecular Cell. See also the Matters Arising Response by Azevedo et al. (2024), published in this issue.
多聚磷酸盐（polyP）是一种由无机磷酸组成的链状物质，存在于所有生命领域，影响着从凝血到癌症等多种细胞现象。Azevedo 等人的一项研究描述了一种蛋白质修饰方式，即多聚磷酸盐通过所谓的共价磷酰胺键与多酸性丝氨酸和赖氨酸（PASK）模体中的赖氨酸残基结合。这主要基于该修饰物在极端变性条件下仍能存活的显著能力。我们的研究表明，赖氨酸多磷酸化是非共价的，其对离子强度和赖氨酸质子化的敏感性以及没有形成磷酰胺键，这可以通过 P NMR 进行分析。离子与赖氨酸残基的相互作用足以进行多聚磷酸盐修饰，我们提出了一个新的非 PASK 赖氨酸重复蛋白的列表，这些蛋白经历了多聚磷酸盐修饰。这项工作阐明了多聚磷酸盐-赖氨酸修饰的生物化学，对研究和调节这一现象都具有重要意义。本期出版的《分子细胞》杂志还刊登了 Azevedo 等人的回应。
