SUMO1 and ciliopathy: CREBP1 (also known as ATF2) has been shown to regulate the expression of five genes, namely, EP300 (an HLHS-associated gene sharing a direct interaction with the ciliopathy gene CRX), SUMO1 (a shared interactor having a novel PPI with the ciliopathy-associated gene MAK and a known PPI with the HLHS-associated gene NCOA1) and three known shared interactors of HLHS and ciliopathy genes (PRNP, SMAD3 and TBX6).