ATRNL1 (attractin like 1) is a transmembrane protein that functions as an adapter in multiple cellular signaling pathways. ATRNL1 serves as a transmembrane adapter that recruits the E3 ubiquitin ligase MGRN1 to promote ubiquitination and degradation of melanocortin receptors MC1R and MC4R, thereby regulating melanocortin signaling pathways involved in energy homeostasis 1. In cardiac tissue, ATRNL1 is overexpressed in cardiomyocytes of patients with atrial fibrillation and localizes to intercalated disks, where it plays a potent role in cell stress response and modulation of cardiac action potentials 2. The protein also functions as a tumor suppressor in cervical cancer, where it is transcriptionally regulated by CEBPB and inhibits epithelial-mesenchymal transition, cell viability, and migration 3. ATRNL1 mutations have been identified in various cancers, including solid pseudopapillary neoplasm of the pancreas and B-cell lymphoma 45. Genetic variants in ATRNL1 may influence metformin treatment response in youth with type 2 diabetes 6. Haploinsufficiency due to ATRNL1 deletion is associated with cognitive impairment, autism, dysmorphic features, and developmental abnormalities 7, highlighting its critical role in human development and disease.