The RING-type zinc finger motif is present in a number of viral and eukaryotic proteins and is made of a conserved cysteine-rich domain that is able to bind two zinc atoms. Proteins that contain this conserved domain are generally involved in the ubiquitination pathway of protein degradation. RNF135 (RING finger protein 135), also known as L13, is a 432 amino acid protein that contains one RING-type zinc finger and one SPRY domain. Via its RING-type zinc finger, RNF135 may play a role in transcriptional regulation and protein degradation events. Defects in the gene encoding RNF135 are the cause of RNF135-related overgrowth syndrome which is characterized by learning disabilities, facial dysmorphism and increased weight and height. Multiple isoforms of RNF135 exist due to alternative splicing events.