SEC16

Sec16, also known as SEC16A, is a protein that plays a crucial role in the endoplasmic reticulum (ER) to Golgi transport pathway. It is a member of the Sec1/Munc18 (SM) protein family, which is involved in vesicular trafficking. Sec16 is primarily localized to the ER and is essential for the formation and fusion of transport vesicles with the Golgi apparatus.

The Sec16 protein consists of several domains, including a Sec1/Munc18 (SM) domain, a coiled-coil domain, and a C-terminal domain. The SM domain is responsible for binding to the Sec18 protein, which is a component of the coat protein complex II (COPII). This interaction is crucial for the recruitment of COPII vesicles to the ER exit sites and their subsequent fusion with the Golgi apparatus.

Sec16 is also involved in the regulation of ER-Golgi transport by interacting with other proteins, such as Sec23 and Sec24. These interactions help to coordinate the assembly and disassembly of the COPII vesicles, ensuring efficient and regulated transport of proteins and lipids between the ER and the Golgi apparatus.

Mutations in the SEC16 gene have been associated with various genetic disorders, including Charcot-Marie-Tooth disease type 2A (CMT2A) and autosomal recessive spastic paraplegia type 3 (ARSP3). These disorders are characterized by peripheral neuropathy and spasticity, respectively, and are caused by defects in the ER-Golgi transport pathway.

In summary, Sec16 is a critical protein involved in the ER to Golgi transport pathway, playing a role in the formation and fusion of transport vesicles. Its interactions with other proteins and its localization to the ER make it essential for the efficient and regulated transport of proteins and lipids within the cell.