Gram domain containing 1a


GRAM domain containing 1A also known as Aster-A is a protein that is encoded by the GRAMD1A gene.
It contains a transmembrane region, a GRAM domain and a VASt domain that can bind cholesterol. GRAMD1A has four paralogs: GRAMD1B and GRAMD1C and two without VASt domains, GRAMD2A and GRAMD2B. These proteins are mammalian representatives of the yeast lipid transfer proteins anchored at a membrane contact site family.

Function

GRAMD1A localizes to the endoplasmic reticulum. Its GRAM domain tethers it to the plasma membrane where it can bind phosphatidylinositol phosphate in areas enriched for it. The protein alters intracellular cholesterol distribution, moving it from the plasma membrane. GRAMD1A also is necessary for autophagosome biogenesis.