Holding Out for a Model: Rhomboid Superfamily in Vertebrate Development and Disease.

The rhomboid superfamily, comprising both proteases and pseudoproteases, has emerged as a central regulator of membrane biology, mediating diverse functions including protein quality control, signal transduction, trafficking, and more. While molecular mechanisms of rhomboid activity have been well-characterized in invertebrate and cell-based systems, their physiological role in vertebrate development remains limited and continues to evolve. Here, we review recent advances in cell culture systems and vertebrate models that uncover the developmental and disease-relevant functions of rhomboid family members, including RHBDLs, iRhoms, PARL, and Derlins. We outline their roles in embryogenesis, tissue regeneration, neurodevelopment, and immune signaling, alongside their pathological involvement in cancer, neurodegeneration, and metabolic disorders. We also emphasize the limitations posed by early embryonic lethality in knockout models and advocate for tissue-specific vertebrate models to dissect rhomboid-dependent pathways in vivo. Understanding how rhomboid proteins coordinate developmental processes will not only reveal fundamental principles of membrane-associated processes, but also open new avenues for therapeutic targeting in disease.