title: Contribution of casein kinase 2 and spleen tyrosine kinase to CFTR trafficking and protein kinase A-induced activity.
abstract: Previously, the pleiotropic "master kinase" casein kinase 2 (CK2) was shown to interact with CFTR, the protein responsible for cystic fibrosis (CF). Moreover, CK2 inhibition abolished CFTR conductance in cell-attached membrane patches, native epithelial ducts, and Xenopus oocytes. CFTR possesses two CK2 phosphorylation sites (S422 and T1471), with unclear impact on its processing and trafficking. Here, we investigated the effects of mutating these CK2 sites on CFTR abundance, maturation, and degradation coupled to effects on ion channel activity and surface expression. We report that CK2 inhibition significantly decreased processing of wild-type (wt) CFTR, with no effect on F508del CFTR. Eliminating phosphorylation at S422 and T1471 revealed antagonistic roles in CFTR trafficking: S422 activation versus T1471 inhibition, as evidenced by a severe trafficking defect for the T1471D mutant. Notably, mutation of Y512, a consensus sequence for the spleen tyrosine kinase (SYK) possibly acting in a CK2 context adjacent to the common CF-causing defect F508del, had a strong effect on both maturation and CFTR currents, allowing the identification of this kinase as a novel regulator of CFTR. These results reinforce the importance of CK2 and the S422 and T1471 residues for regulation of CFTR and uncover a novel regulation of CFTR by SYK, a recognized controller of inflammation.
authors.affiliation: University of Lisbon, BioFIG-Center for Biodiversity, Functional and Integrative Genomics, 1749-016 Lisbon, Portugal.
authors.forename: Simão
authors.initials: S
authors.lastname: Luz
authors.forename: Patthara
authors.initials: P
authors.lastname: Kongsuphol
authors.forename: Ana Isabel
authors.initials: AI
authors.lastname: Mendes
authors.forename: Francisco
authors.initials: F
authors.lastname: Romeiras
authors.forename: Marisa
authors.initials: M
authors.lastname: Sousa
authors.forename: Rainer
authors.initials: R
authors.lastname: Schreiber
authors.forename: Paulo
authors.initials: P
authors.lastname: Matos
authors.forename: Peter
authors.initials: P
authors.lastname: Jordan
authors.forename: Anil
authors.initials: A
authors.lastname: Mehta
authors.forename: Margarida D
authors.initials: MD
authors.lastname: Amaral
authors.forename: Karl
authors.initials: K
authors.lastname: Kunzelmann
authors.forename: Carlos M
authors.initials: CM
authors.lastname: Farinha
mesh_terms: D000818:Animals; D047390:Casein Kinase II / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D006224:Cricetinae; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D007473:Ion Channels / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D009154:Mutation; D010766:Phosphorylation / Q000235:genetics; D021381:Protein Transport; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D000072377:Syk Kinase; D014982:Xenopus laevis
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D007473:Ion Channels; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D011505:Protein-Tyrosine Kinases; D000072377:Syk Kinase; C000606897:Syk protein, mouse; D047390:Casein Kinase II; D017868:Cyclic AMP-Dependent Protein Kinases