The SRAP family functions as a DNA-associated autoproteolytic switch that recruits diverse repair enzymes onto DNA damage. We propose that the human protein Q96FZ2:UniProtKB, the eukaryotic member of the SRAP family, which has been recently shown to bind specifically to DNA with 5-hydroxymethylcytosine, 5-formylcytosine and 5-carboxycytosine, is a sensor for these oxidized bases generated by the TET (tetrahedral aminopeptidase of the M42 family) enzymes from methylcytosine. Hence, its autoproteolytic activity might help it act as a switch that recruits DNA repair enzymes to remove these oxidized methylcytosine species as part of the DNA demethylation pathway downstream of the TET enzymes.

1: Novel autoproteolytic and DNA-damage sensing components in the bacterial SOS response and oxidized methylcytosine-induced eukaryotic DNA demethylation systems. Aravind L, Anand S, Iyer LM; Biol Direct. 2013;8:20. PMID:23945014