Unlike most kinases, phosphatidylinositol 5-phosphate 4-kinase β (PI5P4Kβ) utilizes GTP as a physiological phosphate donor and regulates cell growth under stress (i.e., GTP-dependent stress resilience). However, the genesis and evolution of its GTP responsiveness remain unknown. Here, we reveal that PI5P4Kβ has acquired GTP preference by generating a short dual-nucleotide-recognizing motif called the guanine efficient association (GEA) motif. Comparison of nucleobase recognition with 660 kinases and 128 G proteins has uncovered that most kinases and PI5P4Kβ use their main-chain atoms for adenine recognition, while the side-chain atoms are required for guanine recognition. Mutational analysis of the GEA motif revealed that the acquisition of GTP reactivity is accompanied by an extended activity toward inosine triphosphate (ITP) and xanthosine triphosphate (XTP). Along with the evolutionary analysis data that point to strong negative selection of the GEA motif, these results suggest that the GTP responsiveness of PI5P4Kβ has evolved from a compromised trade-off between activity and specificity, underpinning the development of the GTP-dependent stress resilience.

与大多数激酶不同，磷脂酰肌醇 5-磷酸 4-激酶 β (PI5P4Kβ) 利用 GTP 作为生理磷酸盐供体，并调节应激下的细胞生长（即 GTP 依赖性应激恢复能力）。然而，其 GTP 反应性的起源和进化仍然未知。在这里，我们发现 PI5P4Kβ 通过生成一个称为鸟嘌呤有效关联 (GEA) 基序的短双核苷酸识别基序而获得了 GTP 偏好。与660个激酶和128个G蛋白的核碱基识别比较发现，大多数激酶和PI5P4Kβ使用其主链原子进行腺嘌呤识别，而侧链原子则用于鸟嘌呤识别。GEA 基序的突变分析表明，GTP 反应性的获得伴随着对三磷酸肌苷 (ITP) 和三磷酸黄苷 (XTP) 的延长活性。连同表明 GEA 基序强烈负选择的进化分析数据一起，这些结果表明 PI5P4Kβ 的 GTP 响应性是从活性和特异性之间的妥协权衡演变而来的，支撑了 GTP 依赖性应激恢复能力的发展。