Author(s): Russo D, Wu X, Redman CM, Lee S
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Abstract 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.
This article was published in Blood
and referenced in Journal of Antivirals & Antiretrovirals