title: Kell and Kx, two disulfide-linked proteins of the human erythrocyte membrane are phosphorylated in vivo.
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.
authors.affiliation: INSERM U76, Institut National de la Transfusion Sanguine, Paris, France.
authors.forename: F
authors.initials: F
authors.lastname: Carbonnet
authors.forename: C
authors.initials: C
authors.lastname: Hattab
authors.forename: J P
authors.initials: JP
authors.lastname: Cartron
authors.forename: O
authors.initials: O
authors.lastname: Bertrand
mesh_terms: D000954:Antigens, Surface / Q000737:chemistry*; D047390:Casein Kinase II; D047388:Casein Kinases; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004220:Disulfides / Q000737:chemistry; D004789:Enzyme Activation / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004910:Erythrocyte Membrane / Q000737:chemistry; D004912:Erythrocytes / Q000737:chemistry*; D006801:Humans; D007626:Kell Blood-Group System / Q000737:chemistry*; D008565:Membrane Proteins / Q000737:chemistry*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism; D047428:Protein Kinase Inhibitors; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism
chemical_list: D000954:Antigens, Surface; D004220:Disulfides; D004791:Enzyme Inhibitors; D007626:Kell Blood-Group System; D008565:Membrane Proteins; D047428:Protein Kinase Inhibitors; D011494:Protein Kinases; D047390:Casein Kinase II; D047388:Casein Kinases; D017346:Protein Serine-Threonine Kinases; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C