Sec31B

Sec31B is a protein encoded by the SEC31B gene in humans. It is a component of the COPII (coat protein complex II) vesicle coat, which plays a vital role in mediating the transport of proteins from the endoplasmic reticulum (ER) to the Golgi apparatus. The COPII complex is essential for proper cellular secretion processes and maintaining organelle function.

Sec31B is considered a paralog of SEC31A, another isoform known to participate in COPII vesicle formation. Unlike SEC31A, Sec31B is less studied but is believed to have tissue-specific or regulatory roles within vesicle trafficking pathways. It interacts with other COPII elements such as Sec13, Sec23, and Sar1, contributing to the assembly of the vesicle coat and vesicle budding from the ER membrane.

Structurally, Sec31B contains regions that facilitate protein-protein interactions necessary for coat assembly. Its function is crucial in ensuring the selective transport of cargo proteins, which affects processes such as cell signaling, extracellular matrix composition, and immune responses.

Mutations or dysregulation of the SEC31B gene have been associated with certain disorders, including some forms of cancer and congenital conditions affecting secretion pathways. However, ongoing research continues to clarify its full biological significance and potential as a therapeutic target.

In summary, Sec31B is a key player in vesicle trafficking, contributing to intracellular transport and cellular homeostasis through its role in COPII coat assembly.