The 2 known types of pyrimidine nucleoside phosphorylases, uridine phosphorylase (UP; EC 2.4.2.3) and thymidine phosphorylase (TP; EC 2.4.2.4), in the presence of orthophosphate, catalyze the reversible phosphorolysis of uridine and thymidine or deoxyuridine, respectively, to free bases and ribose-1-phosphate or deoxyribose-1-phosphate. Pyrimidine nucleoside phosphorylases can add ribose or deoxyribose to pyrimidine bases to form nucleosides that can be incorporated into RNA or DNA

Collapsin response mediator proteins (CRMPs), including CRMP-1 (DRP-1), CRMP-2 (DRP-2 or TOAD64), CRMP-3 (DRP-4), CRMP-4 (DRP-3) and CRMP-5 (DRP-5), mediate signal transduction after exposure of neural cells to the axon guidance molecule Semaphorin 3A (SEMA3A)/collapsin. CRMPs are present in the developing cerebral cortex and neocortical neurons and are responsive to SEMA3A. In the adult brain, the expression of CRMPs is dramatically downregulated. However, they remain expressed in structure

This gene encodes a component of the Mediator complex. The Mediator complex interacts with DNA-binding gene-specific transcription factors to modulate transcription by RNA polymerase II. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene. [provided by RefSeq, Jul 2012]