SEC24C

Sec24C is a protein encoded by the SEC24C gene in humans and is a member of the Sec24 family that forms part of the COPII vesicle coat. COPII mediates transport of proteins from the endoplasmic reticulum to the Golgi apparatus, and Sec24 proteins contribute to cargo selection within the inner coat of these vesicles. In vertebrates there are four Sec24 paralogs—Sec24A, Sec24B, Sec24C, and Sec24D—that assemble with Sec23 to create the Sec23–Sec24 heterodimer, which pairs with the outer coat components Sec13 and Sec31 to generate COPII vesicles.

Sec24C functions as a cargo adaptor, recognizing export signals on cargo proteins or cargo receptors and promoting their inclusion into COPII vesicles. Different Sec24 paralogs have overlapping yet distinct cargo preferences, enabling cell-type- and development-specific trafficking programs. At ER exit sites, Sec24C activity is coordinated with other COPII components and regulatory factors that influence vesicle budding and cargo selection.

Genetic or functional disruption of Sec24C in model organisms disrupts COPII trafficking and often leads to severe developmental defects or embryonic lethality, highlighting its essential role in secretion. In humans, rare variants in SEC24C have been reported in association with neurodevelopmental disorders, but the evidence is preliminary and requires further validation.

Sec24C remains a conserved component of the COPII machinery, contributing to the diversity of cargo handling across tissues by providing paralog-specific cargo recognition within the secretory pathway.