This gene encodes a regulator of cyclin-dependent kinase 5 activity. This protein has also been reported to modify RNA by adding a methylthio-group and may thus have a dual function as an RNA methylthiotransferase and as an inhibitor of cyclin-dependent kinase 5 activity. Alternative splicing results in multiple transcript variants that encode different isoforms. [provided by RefSeq, May 2013] see less This gene encodes a regulator of cyclin-dependent kinase 5 activity. This protein has also been reported to modify RNA by adding a methylthio-group and may thus have a dual function as an RNA methylthiotransferase and as an inhibitor of cyclin-dependent kinase 5 activity. Alternative splicing results in multiple transcript variants that encode different isoforms. [provided by RefSeq, May 2013]