[Integral proteins of red cell membranes: their genetic and phenotypic expressions]

Integral proteins of human red cell membranes are reviewed from the standpoint of genetic and phenotypic expressions. Band 3 plays an important role in anion exchange transport at its membrane domain and in its binding to cytoskeletal membrane proteins and cytosolic components. Several possible mechanisms for band 3 gene expression are also discussed. The abnormalities of band 3 were detected in hereditary elliptocytosis, especially Southeast Asian ovalocytosis, and also in hereditary spherocytosis associated with deficiency of band 3 protein. A complete deficiency of band 3 has recently been discovered in cattle, which demonstrated a markedly increased hemolysis, impaired anion transport, and striking instability of cytoskeletal network with extensive microspherocytosis. Glycophorins are the other major integral proteins, and consisted of the two major categories; i.e., glycophorin A (GPA)-glycophorin B (GPB)-glycophorin E (GPE) and glycophorin C (GPC)-glycophorin D (GPD). Genetically, GPB gene appears to be derived from the duplication of GPA gene and insertion of the Alu-Alu structure. GPE gene appears to be formed basically by duplication of GPB gene. Several mutation of the GPA-GPB-GPE system have been reported; En(a-) phenotype by skipping GPA gene, S-s-U-phenotype with by skipping GPB gene, and MKMK phenotype by skipping both GPA and GPB genes. Hybrid forms of GPA and GPB have also been known as Miltenberger V and Sta. GPD appears to be a truncated form of GPC. Several mutation have also been known as Melanesian (Ge: -1), Yus (Ge: -2, 3, 4), Gerbich (Ge: -2, -3, 4), and Leach (Ge: -2, -3, -4).