GRAMD1B
Description
The GRAMD1B (GRAM domain containing 1B) is a protein-coding gene located on chromosome 11.
GRAMD1B, also known as GRAMD1B, Aster-B, and KIAA1201, is a cholesterol transport protein encoded by the GRAMD1B gene. It has a transmembrane region and two functional domains: the GRAM domain and a VASt domain. It is anchored to the endoplasmic reticulum. This highly conserved gene is found in various vertebrates and invertebrates. Homologs (Lam/Ltc proteins) are found in yeast. GRAMD1B, also known as KIAA1201, is located in the human genome at 11q24.1. It is on the + strand and is surrounded by other genes. It spans 269,347 bases. The most verified isoform, isoform 1, has 21 exons. There are four validated isoform variants of human GRAMD1B. These have shortened 5’ and 3’ regions, resulting in the loss of an exon.
GRAMD1B is a cholesterol transporter that moves cholesterol from the plasma membrane (PM) to the endoplasmic reticulum (ER) without using vesicles. It has special domains that bind to cholesterol and the PM, acting as a bridge for cholesterol transfer. GRAMD1B is important for maintaining cholesterol levels in the adrenal gland and can move to the PM based on the amount of cholesterol in the membrane. When there's not enough cholesterol, it stays in the ER membrane. However, when there's extra cholesterol in the PM, GRAMD1B goes to the contact points between the ER and the PM (EPCS). This movement is controlled by its GRAM domain. At the EPCS, the VASt/ASTER domain binds to cholesterol in the PM and helps move it to the ER.
GRAMD1B is also known as LINC01059.
