title: Functional interaction between the Ser/Thr kinase PKL12 and N-acetylglucosamine kinase, a prominent enzyme implicated in the salvage pathway for GlcNAc recycling.
abstract: PKL12 (STK16) is a ubiquitously expressed Ser/Thr kinase, not structurally related to the well known subfamilies, with a putative role in cell adhesion control. Yeast two-hybrid protein interaction screening was used to search for proteins that associate with PKL12 and to delineate signaling pathways and/or regulatory circuits in which this kinase participates. One positive clone contained an open reading frame highly similar to N-acetylglucosamine kinase (GlcNAcK) of several species. The PKL12/GlcNAcK interaction was further confirmed both in vitro and in vivo. Protein expression analysis of GlcNAcK using a specific rabbit antiserum displayed a ubiquitous pattern in cell lines and animal tissues. Subcellular localization studies showed that GlcNAcK is a cytoplasmic protein with a dual subcellular localization, distributed between the perinuclear and peripheral cell reservoirs. After overexpression, GlcNAcK localizes in vesicular structures associated mainly with the cell membrane and colocalizes with the PKL12 protein. GlcNAcK is not otherwise a substrate for PKL12 activity and PKL12 does not appear to influence GlcNAcK activity either in vitro or in vivo. In vitro kinase assays have nonetheless revealed that functional GlcNAcK, although not able to modulate autophosphorylation of PKL12, greatly influences PKL12 kinase activity on a defined substrate protein. These results are interpreted to indicate a potential in vivo role for GlcNAcK in PKL12 translocation and a tentative regulatory role for PKL12-mediated phosphorylation on substrate proteins.
authors.affiliation: Departamento de Inmunologia y Oncologia, Protein Design Group, Centro Nacional de Biotecnologia, Spanish Council for Scientific Research, Campus de la Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid, Spain.
authors.forename: Jose Manuel
authors.initials: JM
authors.lastname: Ligos
authors.forename: Teresa Laín
authors.initials: TL
authors.lastname: de Lera
authors.forename: Stephan
authors.initials: S
authors.lastname: Hinderlich
authors.forename: Bárbara
authors.initials: B
authors.lastname: Guinea
authors.forename: Luis
authors.initials: L
authors.lastname: Sánchez
authors.forename: Ramón
authors.initials: R
authors.lastname: Roca
authors.forename: Alfonso
authors.initials: A
authors.lastname: Valencia
authors.forename: Antonio
authors.initials: A
authors.lastname: Bernad
mesh_terms: D016475:3T3 Cells; D000117:Acetylglucosamine / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D017931:DNA Primers; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D015723:Gene Library; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors; D014162:Transfection
chemical_list: D017931:DNA Primers; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors; D005982:Glutathione Transferase; D011494:Protein Kinases; D017853:Phosphotransferases (Alcohol Group Acceptor); C486000:Stk16 protein, mouse; C018716:N-acetylglucosamine kinase; D017346:Protein Serine-Threonine Kinases; C418980:STK16 protein, human; D000117:Acetylglucosamine