AUP1
Description
The AUP1 (AUP1 lipid droplet regulating VLDL assembly factor) is a protein-coding gene located on chromosome 2.
AUP1 is a protein encoded by the AUP1 gene in humans. It contains a domain with homology to the ancient conserved region of the archain 1 gene and a domain that may be involved in binding ubiquitin-conjugating enzymes. AUP1 binds to the conserved membrane-proximal sequence of the cytoplasmic tail of integrin alpha (IIb) subunits, which are crucial for integrin alpha (IIb) beta (3) inside-out signaling in platelets and megakaryocytes. This signaling leads to platelet aggregation and thrombus formation. The AUP1 gene overlaps with the gene for mitochondrial serine protease 25. AUP1 has been shown to interact with ITGA2B.
AUP1 is involved in the translocation of misfolded proteins from the endoplasmic reticulum (ER) to the cytoplasm for proteasomal degradation. It plays a crucial role in lipid droplet formation, clustering, and the regulation of lipid metabolism. AUP1 recruits the ubiquitin-conjugating enzyme UBE2G2 to lipid droplets, facilitating its interaction with ubiquitin ligases AMFR/gp78 and RNF139/TRC8. This leads to the sterol-induced ubiquitination of HMGCR and its subsequent degradation by the proteasome. AUP1 is also required for the degradation of INSIG1, SREBF1, and SREBF2. Furthermore, AUP1 regulates the assembly and secretion of very low density lipoprotein (VLDL) particles and the stability of apolipoprotein APOB.
AUP1 is also known as -.
