Protein kinase A-dependent phosphorylation of Lutheran/basal cell adhesion molecule glycoprotein regulates cell adhesion to laminin alpha5.
Lutheran (Lu) blood group and basal cell adhesion molecule (B-CAM) antigens reside on two glycoprotein (gp) isoforms Lu and Lu(v13) that belong to the Ig superfamily and differ only by the size of their cytoplasmic tail. Lu/B-CAM gps have been recognized as laminin alpha5 receptors on red blood cells and epithelial cells in multiple tissues. It has been shown that sickle red cells exhibit enhanced adhesion to laminin alpha5 when intracellular cAMP is up-regulated by physiological stimuli such as epinephrine and that this signaling pathway is protein kinase A- and Lu/B-CAM-dependent. In this study, we analyzed the relationship between the phosphorylation status of Lu/B-CAM gps and their adhesion function to laminin alpha5. We showed that Lu isoform was phosphorylated in sickle red cells as well as in erythroleukemic K562 and epithelial Madin-Darby canine kidney cells and that this phosphorylation is enhanced by different stimuli of the PKA pathway. Lu gp is phosphorylated by glycogen synthase kinase 3 beta, casein kinase II, and PKA at serines 596, 598, and 621, respectively. Alanine substitutions of serines 596 and 598 abolished phosphorylation by glycogen synthase kinase 3 beta and casein kinase II, respectively, but had no effect on adhesion of K562 cells to laminin under flow conditions. Conversely, mutation of serine 621 prevented phosphorylation by PKA and dramatically reduced cell adhesion. Furthermore, stimulation of K562 cells by epinephrine increased Lu gp phosphorylation by PKA and enhanced adhesion to laminin. It is postulated that modulation of the phosphorylation state of Lu gp might be a critical factor for the sickle red cells adhesiveness to laminin alpha5 in sickle cell disease.
INSERM U665, Paris, F-75015, France.
Emilie
E
Gauthier
Cécile
C
Rahuel
Marie Paule
MP
Wautier
Wassim
W
El Nemer
Pierre
P
Gane
Jean Luc
JL
Wautier
Jean Pierre
JP
Cartron
Yves
Y
Colin
Caroline
C
Le Van Kim
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000409:Alanine / Q000737:chemistry; D000595:Amino Acid Sequence; D000755:Anemia, Sickle Cell / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D002078:Butoxamine / Q000494:pharmacology; D047390:Casein Kinase II / Q000378:metabolism; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000737:chemistry*; D002460:Cell Line; D005576:Colforsin / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D004285:Dogs; D004837:Epinephrine / Q000737:chemistry / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology; D004912:Erythrocytes / Q000166:cytology; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D006023:Glycoproteins / Q000737:chemistry; D006801:Humans; D047468:Immunoprecipitation; D020014:K562 Cells; D007668:Kidney / Q000166:cytology; D007797:Laminin / Q000737:chemistry* / Q000378:metabolism; D008188:Lutheran Blood-Group System; D008969:Molecular Sequence Data; D009154:Mutation; D009363:Neoplasm Proteins / Q000737:chemistry*; D010766:Phosphorylation; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry; D012694:Serine / Q000737:chemistry; D015398:Signal Transduction; D015854:Up-Regulation
D000319:Adrenergic beta-Antagonists; C090228:BCAM protein, human; D015815:Cell Adhesion Molecules; D006023:Glycoproteins; D007797:Laminin; D008188:Lutheran Blood-Group System; D009363:Neoplasm Proteins; D011994:Recombinant Proteins; C097043:laminin alpha5; D002078:Butoxamine; D005576:Colforsin; D012694:Serine; D000242:Cyclic AMP; D047390:Casein Kinase II; D000071679:Glycogen Synthase Kinase 3 beta; D017868:Cyclic AMP-Dependent Protein Kinases; D038362:Glycogen Synthase Kinase 3; D000409:Alanine; D004837:Epinephrine