SEC24A

SEC24A is a gene that encodes a subunit of the COPII (Coat Protein Complex II) coat. COPII is a protein complex responsible for the selective transport of cargo proteins from the endoplasmic reticulum (ER) to the Golgi apparatus in eukaryotic cells. This transport pathway is essential for protein secretion and the proper functioning of the secretory pathway.

Specifically, SEC24A is one of four mammalian paralogs (SEC24A, SEC24B, SEC24C, and SEC24D) of the Sec24 protein, which is a key component of the COPII inner coat. The Sec24 subunit directly binds to the cytoplasmic tails of cargo proteins that are destined for export from the ER. This binding is selective, meaning that different Sec24 paralogs exhibit preferences for specific cargo proteins, thus playing a role in cargo selection and sorting.

The SEC24A gene is located on human chromosome 14q13.3. Mutations in SEC24A have been associated with certain genetic disorders, including cranio-lenticulo-calcaneal dysplasia (CLCD), a rare skeletal dysplasia characterized by abnormalities in bone development, the skull, and the lens of the eye. The severity of the phenotype can vary depending on the specific mutation.

The SEC24A protein contains several domains, including a Sec23-binding domain (which mediates interaction with another COPII subunit, Sec23) and cargo-binding sites. The precise mechanism by which SEC24A selects its cargo and promotes COPII assembly is still an area of active research. Understanding the function of SEC24A is important for understanding the fundamental mechanisms of protein trafficking and the pathogenesis of diseases associated with its dysfunction.