This gene encodes a tumor suppressor protein that reduces cell growth by stimulating apoptosis. The first intron of this gene contains the neuronatin gene, which is imprinted and only expressed from the paternal allele. This gene is imprinted in brain where it is differentially expressed from different promoters. Transcription from the upstream promoter occurs preferentially on the maternal allele, and transcripts are preferentially expressed from the downstream promoter on the paternal allele. Alternative promoters and alternative splicing result in multiple transcript variants that encode the same protein.[provided by RefSeq, Nov 2009]