SAR1B

Function

Involved in transport from the endoplasmic reticulum to the Golgi apparatus. Activated by the guanine nucleotide exchange factor PREB. Involved in the selection of the protein cargo and the assembly of the COPII coat complex.

Involvement in disease

Chylomicron retention disease

CMRD

An autosomal recessive disorder of severe fat malabsorption associated with failure to thrive in infancy. The condition is characterized by deficiency of fat-soluble vitamins, low blood cholesterol levels, and a selective absence of chylomicrons from blood. Affected individuals accumulate chylomicron-like particles in membrane-bound compartments of enterocytes, which contain large cytosolic lipid droplets.

None

The disease is caused by variants affecting the gene represented in this entry.

Sequence similarities

Belongs to the small GTPase superfamily. SAR1 family.

Tissue specificity

Expressed in many tissues including small intestine, liver, muscle and brain.

Cellular localization

• Endoplasmic reticulum membrane
• Peripheral membrane protein
• Golgi apparatus
• Golgi stack membrane
• Peripheral membrane protein
• Associated with the endoplasmic reticulum and Golgi stacks, in particular in the juxta-nuclear Golgi region.

Alternative names

• GTP-binding protein SAR1b
• GTP-binding protein B
• GTBPB
• SAR1B
• SARA2
• SARB

Database links

• entrezGene:51128
• omim:607690
• swissprot:Q9Y6B6

Target type

Proteins

Molecular weight

22410Da