Melanoma Associated Retinopathy (MAR) is a paraneoplastic visual syndrome associated with cutaneous malignant melanoma in which patients typically experience a sudden decrease in night vision and sensations of shimmering lights. Electroretinogram (ERG) recordings from MAR patients are characterized by a negative waveform in which the a-wave, arising from photoreceptor transduction, is normal, but the b-wave, arising primarily from ON-bipolar cell activation, is absent or reduced. Significantly, serum from MAR patients has been shown to label retinal bipolar cells. The proposed research tests the hypothesis that autoantibodies in MAR patient serum are generated against proteins expressed in metastatic malignant melanocytes, but then target a protein complex functional in bipolar cells. The aims of the research are to identify the retinal antigens in MAR, to elucidate the role of these proteins in normal bipolar cell physiology, and determine how these functions are perturbed in MAR. The aims will be addressed with a multidisciplinary approach combining immunohistochemistry, cell biology, biochemistry, and electrophysiology. The results will generate new insights into cellular processes fundamental to vision and will contribute to our understanding of the link between cancer and autoimmune retinopathy.