Clusterin-Like Protein 1 (CLUL1) is a secreted protein that belongs to the clusterin family. CLUL1 is synthesized as a 466 amino acid precursor that contains a 20 amino acid signal sequence, and a 446 amino acid mature chain. CLUL1 is expressed predominantly by cone photoreceptors of the retina. It has been shown that CLUL1 expression is down-regulated in some forms of retinal disease.