GRAM domain-containing protein 1B (GRAMD1B)

GRAM domain-containing protein 1B (GRAMD1B, also known as Aster-B and KIAA1201) is an integral membrane cholesterol transport protein anchored to the endoplasmic reticulum[1]. It contains a GRAM domain and a VASt (StAR-related lipid transfer) domain, which together enable the protein to mediate the nonvesicular transport of cholesterol from the plasma membrane to the endoplasmic reticulum at membrane contact sites, particularly in response to high cholesterol load[1][2][3][4]. GRAMD1B is highly conserved across species, expressed in many human tissues (notably adrenal gland, gonads, brain, and placenta), and plays critical roles in cellular lipid regulation, autophagy, and maintenance of cholesterol homeostasis. In neuronal systems, it impacts tau phosphorylation and clearance via the autophagy pathway, with implications for neurodegenerative disease pathogenesis[3]. Experimentally, AI-3d can inhibit GRAMD1B, impacting cholesterol and tau regulation, but broader drug targeting remains limited. There are no current safety reports specific to its therapeutic targeting, but loss of function impairs cholesterol and lipid trafficking, indicating potential for homeostatic disruption[3].

Other names

Protein Aster-BKIAA1201UNQ3032/PRO9834Aster-BGRAM domain-containing protein 1Blong intergenic non-protein coding RNA 1059LINC01059

Inhibition of nonvesicular cholesterol transfer and lipid trafficking