Based on limited published evidence, TEX261 encodes a protein involved in ER-to-Golgi vesicle-mediated transport. It functions as a COPII receptor on endoplasmic reticulum and Golgi membranes, facilitating COPII-coated vesicle formation during secretory pathway transport. In a comprehensive screening of testis-expressed genes in infertile men, TEX261 knockdown in Drosophila resulted in normal fertility, suggesting it is not essential for spermatogenesis 1.