Anti-N3-Phosphohistidine (3-pH

N3-phosphohistidine (3-pHis) is a post-translational modification of the amino acid histidine, where a phosphate group is added to the nitrogen atom of the imidazole ring at the 3-position. This modification plays an important role in cellular signaling, particularly in signal transduction pathways that involve histidine kinases. Unlike the more commonly studied serine, threonine, and tyrosine phosphorylation, 3-pHis is less understood but is emerging as an important regulatory mechanism in bacterial systems and certain eukaryotic processes. In particular, 3-pHis is involved in histidine kinase-mediated signal transduction, a key component of two-component signaling systems that allow cells to respond to environmental stimuli. It has also been implicated in regulating protein-protein interactions, enzyme activity, and metabolic processes. The study of 3-pHis is an active area of research in phosphorylation-based signaling, with growing interest in its role in cellular regulation and disease processes, including cancer and inflammation.