Small integral membrane protein 1 (SMIM1)

Small integral membrane protein 1 (SMIM1) is a 78-amino acid single-pass transmembrane protein encoded on chromosome 1, serving as the carrier for the Vel blood group antigen on red blood cells[1][2][4][5][6][7]. The Vel antigen is of high frequency, but rare individuals lack its expression due to homozygous deletions or mutations in SMIM1, and these Vel-negative individuals can develop anti-Vel antibodies resulting in hemolytic transfusion reactions[2][4][6]. SMIM1 is predominantly expressed in hematopoietic cells and is post-translationally modified; its membrane orientation is tail-anchored, with the C-terminus extracellular and most of the protein cytoplasmic[1][3][4]. Despite its clinical importance in transfusion medicine, the precise physiological role of SMIM1 in erythropoiesis and red cell biology remains poorly understood[1][4][7]. No therapeutics target SMIM1, but genetic and serological identification is crucial for safe blood transfusion practices[2][4][5][6].

Other names

Vel blood group antigenVelblood group VEL proteinVel protein

null (no drugs act by modulating SMIM1)