title: Phosphorylation of multifunctional galectins by protein kinases CK1, CK2, and PKA.
abstract: Phosphorylation is known to have a strong impact on protein functions. We analyzed members of the lectin family of multifunctional galectins as targets of the protein kinases CK1, CK2, and PKA. Galectins are potent growth regulators able to bind both glycan and peptide motifs at intra- and extracellular sites. Performing in vitro kinase assays, galectin phosphorylation was detected by phosphoprotein staining and autoradiography. The insertion of phosphoryl groups varied to a large extent depending on the type of kinase applied and the respective galectin substrate. Sites of phosphorylation observed in the recombinant galectins were determined by a strategic combination of phosphopeptide enrichment and nano-ultra-performance liquid chromatography tandem mass spectrometry (nanoUPLC-MS/MS). By in silico modeling, phosphorylation sites were visualized three-dimensionally. Our results reveal galectin-type-specific Ser-/Thr-dependent phosphorylation beyond the known example of galectin-3. These data are the basis for functional studies and also illustrate the analytical sensitivity of the applied methods for further work on human lectins.
authors: Biomolecular Interactions, German Cancer Research Center, 69120 Heidelberg, Germany. Electronic address: d.kuebler@dkfz.de.
authors: Dieter
authors: D
authors: Kübler
authors: SGS M-Scan, 79108 Freiburg, Germany.
authors: Jörg
authors: J
authors: Seidler
authors: Institute of Physiological Chemistry, Faculty of Veterinary Medicine, Ludwig Maximilians University Munich, 80539 Munich, Germany.
authors: Sabine
authors: S
authors: André
authors: Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA.
authors: Sonu
authors: S
authors: Kumar
authors: Translational Immunology, German Cancer Research Center, 69120 Heidelberg, Germany.
authors: Reinhard
authors: R
authors: Schwartz-Albiez
authors: Core Facility Molecular Structural Analysis, German Cancer Research Center, 69120 Heidelberg, Germany.
authors: Wolf-Dieter
authors: WD
authors: Lehmann
authors: Institute of Physiological Chemistry, Faculty of Veterinary Medicine, Ludwig Maximilians University Munich, 80539 Munich, Germany.
authors: Hans-Joachim
authors: HJ
authors: Gabius
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D047389:Casein Kinase I / Q000378:metabolism*; D047390:Casein Kinase II / Q000378:metabolism*; D002645:Chickens; D002851:Chromatography, High Pressure Liquid; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D037161:Galectins / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D010766:Phosphorylation; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D053719:Tandem Mass Spectrometry
chemical_list: D037161:Galectins; D011994:Recombinant Proteins; D047389:Casein Kinase I; D047390:Casein Kinase II; D017868:Cyclic AMP-Dependent Protein Kinases
keywords: Galectins; Glycan; Kinases; Lectin; Phosphorylation sites; Protein structure