Rods & rings

Rods and rings (RRs) are poorly characterized fibrous cytoplasmic structures, shaped as a mixture of circular rings and linear rods, that have been observed in cultured human cell lines. Rods and rings are commonly shown to contain inosine monophosphate dehydrogenase (IMPDH) and/or cytidine triphosphate synthetase (CTPS), suggesting a role related to synthesis of nucleotides. Indeed, they seem to be induced by drugs or conditions that deplete the cellular pool of GTP or CTP. Several other proteins have also been found to localize to rods and rings, suggesting a more complex structure, and perhaps also regulation of RRs.

Immunofluorescent staining

Rods and rings were named after their rod- and ring-like shapes. They can be seen in the cytosol, but can vary in both size and numbers.

Read more about the proteome of rods and rings as a substructure of the cytosol.