Abstract
ABSTRACT
Inositol phosphates (InsPs) and inositol pyrophosphates (PP‐InsPs) constitute a remarkably diverse yet evolutionarily conserved signaling network generated through combinatorial phosphorylation of
myo
‐inositol. Despite their widespread presence across eukaryotes, progress in understanding their biology was long constrained by major analytical challenges arising from their extreme charge density, structural similarity, and isomer diversity. The advent of new analytical approaches is now transforming the field. High‐resolution analytical platforms, including capillary‐electrophoresis mass spectrometry, liquid‐chromatography mass spectrometry, and inductively coupled plasma‐based detection, enable sensitive quantification and isomer discrimination. Parallel developments in chemical synthesis, stable‐isotope labeling, and NMR spectroscopy provide essential reference standards and permit investigation of their metabolic turnover in living systems. These developments have uncovered unrecognized InsP and PP‐InsP isomers, revealed substantial variation in metabolic networks across organisms and cell types, and exposed unexpectedly dynamic turnover. Emerging biological insights highlight InsPs and PP‐InsPs as versatile cellular regulators that link metabolism to cellular signaling, influencing cellular energetics and phosphate homeostasis. These messengers are involved in diverse processes both in the cytoplasm and in the nucleus, controlling protein complex assembly and protein pyrophosphorylation. Together, these advances shed light on InsPs and PP‐InsPs as adaptable signaling molecules and open new avenues for deciphering their physiological roles in health and disease.