This gene encodes a protein that associates with the enzyme phosphoribosylpyrophosphate synthetase (PRS). PRS catalyzes the formation of phosphoribosylpyrophosphate which is a substrate for synthesis of purine and pyrimidine nucleotides, histidine, tryptophan and NAD. PRS exists as a complex with two catalytic subunits and two associated subunits. This gene encodes a non-catalytic associated subunit of PRS. Alternate splicing results in multiple transcript variants. [provided by RefSeq, Sep 2011].