Interleukin-31 receptor A (IL-31RA) is a newly identified type I cytokine receptor, that is related to gp130, the common receptor of the interleukin (IL) -6 family cytokines. IL-31RA forms a functional receptor complex for IL-31 together with the beta subunit of oncostatin M receptor (OSMRbeta). OSMRbeta is expressed in a subset of small-sized nociceptive neurons of adult dorsal root ganglia (DRGs).IL-31 and OSM may thus have redundant functions in the development of OSMRbeta-expressing neurons.