RPIA, ribose 5-phosphate isomerase-A, is an enzyme-encoding gene. It is a key enzyme in the pentose phosphate pathway, which is crucial for producing NADPH and pentose precursors for nucleotides. This pathway runs parallel to central glycolysis. The gene plays a significant role in multiple biological processes, including cell proliferation, metabolism, and in maintaining redox control [2,3,4,5,6].

Mutations in RPIA have been associated with a rare genetic leukoencephalopathy [1]. In Enterobacter cloacae, mutation of rpiA decreased seed and root colonization and biocontrol of damping-off caused by Pythium ultimum on cucumber, indicating its role in plant-microbe interactions [4]. In human cancer cells, targeting RPIA can impact cell proliferation. For example, in colorectal cancer cells, miR124 reduces the pentose phosphate pathway and proliferation by targeting RPIA mRNA. Also, in endometrial cancer cells, knockdown of RPIA reduces cell proliferation, accompanied by decreased glycolytic capacity and oxidative phosphorylation [2,3]. In macrophages, the antiviral effector PKR phosphorylates and inhibits RPIA, suppressing nucleic acid production during the immune response to RNA [6].

In conclusion, RPIA is essential for the pentose phosphate pathway and has far-reaching impacts on various biological processes. Studies on RPIA-related loss-of-function in different organisms and cell types, including in cancer and in response to infection, have revealed its significance in disease-related processes, providing potential targets for treatment strategies.