Expression of Kell blood group protein in nonerythroid tissues

• Published in: Blood Vol. 96; no. 1; pp. 340 - 346
• Main Authors: RUSSO, D, XU WU, REDMAN, C. M, SOOHEE LEE
• Format: Journal Article
• Language: English
• Published: Washington, DC The Americain Society of Hematology 01.07.2000
• Subjects: Amino Acid Transport Systems, Neutral; Animals; Biological and medical sciences; Brain - metabolism; Carrier Proteins - metabolism; DNA Primers; DNA, Complementary; Exons; Female; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Gene Library; Kell Blood-Group System - genetics; Male; Membrane Proteins - metabolism; Mice; Muscle, Skeletal - metabolism; Organ Specificity; Polymerase Chain Reaction; Pregnancy; Testis - metabolism; Tissue, organ and graft immunology; Human; Tissue; Blood group; Gene expression; Kell system; Distribution
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.v96.1.340

The Kell blood group protein is a zinc endopeptidase that yields endothelin-3, a potent bioactive peptide, by cleavage of big endothelin-3, a larger intermediate precursor. On red cells, Kell protein is linked by a single disulfide bond to XK, a protein that traverses the membrane 10 times and whose absence, as occurs in the McLeod phenotype, is associated with a set of clinical symptoms that include nerve and muscle disorders and red cell acanthocytosis. Previous studies indicated that Kell is primarily expressed in erythroid tissues, whereas XK has a wider tissue distribution. The tissue distribution of Kell protein has been further investigated by Northern blot analysis, PCR-screening of tissue complementary DNAs (cDNAs), and Western immunoblots. Screening of an RNA dot-blot panel confirmed that Kell is primarily expressed in erythroid tissues but is also expressed in a near equal amount in testis, with weaker expression in a large number of other tissues. PCR-screening of cDNAs from different tissues and DNA sequencing of the products gave similar results. In 2 of the nonerythroid tissues tested, testis and skeletal muscle, Kell protein was detected by Western immunoblotting. In skeletal muscle, isolation of XK with a specific antibody coisolated Kell protein. These studies demonstrate that Kell is expressed in both erythroid and nonerythroid tissues and is associated with XK.