Sar1b is a protein that plays a crucial role in the transport of proteins and lipids within cells. It is part of the Sar1 family, which is involved in the formation of transport vesicles that carry materials from the endoplasmic reticulum to the Golgi apparatus. This protein is essential for maintaining cellular function and communication. Mutations or dysfunctions in Sar1b can lead to various health issues, including Cholestasis, a condition that affects bile flow in the liver. Understanding Sar1b is important for developing treatments for related diseases.