Based on limited published evidence, FERRY3 is a component of the FERRY complex (Five-subunit Endosomal Rab5 and RNA/ribosome intermediary), a RAB5A effector that interacts directly with mRNAs and mediates their endosomal transport and localization 1. The complex recruits mRNAs and ribosomes to early endosomes, functioning in local mRNA distribution, particularly in cells with extended processes 1. FERRY3 also plays a role in mast cell degranulation 1. Mutations in FERRY3 cause autosomal recessive intellectual developmental disorder 66 2, suggesting critical neurobiological functions.