1. Kell and Kx, two disulfide-linked proteins of the human erythrocyte membrane are phosphorylated in vivo.
- Author
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Carbonnet F, Hattab C, Cartron JP, and Bertrand O
- Subjects
- Casein Kinase II, Casein Kinases, Cyclic AMP-Dependent Protein Kinases metabolism, Disulfides chemistry, Enzyme Activation physiology, Enzyme Inhibitors pharmacology, Erythrocyte Membrane chemistry, Humans, Phosphorylation, Protein Kinase C metabolism, Protein Kinase Inhibitors, Protein Kinases metabolism, Protein Serine-Threonine Kinases metabolism, Antigens, Surface chemistry, Erythrocytes chemistry, Kell Blood-Group System chemistry, Membrane Proteins chemistry
- Abstract
Kell and Kx are two quantitatively minor proteins from the human erythrocyte membrane which carry blood groups antigens and are thought to be a metalloprotease and a membrane transporter, respectively. In the red cell membrane, these proteins form a complex stabilized by disulfide bond(s). Phosphorylation status of these proteins was studied, in the presence or absence of effectors of several kinases, either on intact cells incubated with [32P]-orthophosphate or on ghosts incubated with [gamma-32P]ATP. Purification of Kell-Kx complex, by immunochromatography on an immobilized human monoclonal antibody of Kell blood group specificity allowed to establish that (i) neither protein is phosphorylated on tyrosine; (ii) the Kell protein is a putative substrate for Casein Kinase II (CKII) and Casein Kinase I (CKI) but not for protein kinase C (PKC), whereas Kx protein is phosphorylated by CKII and PKC but not by CKI; (iii) Protein Kinase A neither phosphorylates the Kell nor the Kx proteins.
- Published
- 1998
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