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Integrin-linked kinase is a functional Mn²⁺-dependent protein kinase that regulates glycogen synthase kinase-3β (GSK-3beta) phosphorylation.

Maydan, Mykola and McDonald, Paul C and Sanghera, Jasbinder and Yan, Jun and Rallis, Charalampos and Pinchin, Sheena and Hannigan, Gregory E and Foster, Leonard J and Ish-Horowicz, David and Walsh, Michael P and Dedhar, Shoukat (2010) 'Integrin-linked kinase is a functional Mn²⁺-dependent protein kinase that regulates glycogen synthase kinase-3β (GSK-3beta) phosphorylation.' PLoS One, 5 (8). ISSN 1932-6203

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Abstract

Background Integrin-linked kinase (ILK) is a highly evolutionarily conserved, multi-domain signaling protein that localizes to focal adhesions, myofilaments and centrosomes where it forms distinct multi-protein complexes to regulate cell adhesion, cell contraction, actin cytoskeletal organization and mitotic spindle assembly. Numerous studies have demonstrated that ILK can regulate the phosphorylation of various protein and peptide substrates in vitro, as well as the phosphorylation of potential substrates and various signaling pathways in cultured cell systems. Nevertheless, the ability of ILK to function as a protein kinase has been questioned because of its atypical kinase domain. Methodology/principal findings Here, we have expressed full-length recombinant ILK, purified it to >94% homogeneity, and characterized its kinase activity. Recombinant ILK readily phosphorylates glycogen synthase kinase-3 (GSK-3) peptide and the 20-kDa regulatory light chains of myosin (LC(20)). Phosphorylation kinetics are similar to those of other active kinases, and mutation of the ATP-binding lysine (K220 within subdomain 2) causes marked reduction in enzymatic activity. We show that ILK is a Mn-dependent kinase (the K(m) for MnATP is approximately 150-fold less than that for MgATP). Conclusions/significance Taken together, our data demonstrate that ILK is a bona fide protein kinase with enzyme kinetic properties similar to other active protein kinases.

Item Type: Article
Uncontrolled Keywords: Cell Line, Animals, Humans, Manganese, Microfilament Proteins, Protein-Serine-Threonine Kinases, Glycogen Synthase Kinase 3, Lysine, Peptides, Actinin, Recombinant Proteins, Adenosine Triphosphate, Enzyme Inhibitors, Mutagenesis, Site-Directed, Enzyme Activation, Substrate Specificity, Phosphorylation, Kinetics, Mutation, Glycogen Synthase Kinase 3 beta
Divisions: Faculty of Science and Health > Life Sciences, School of
Depositing User: Elements
Date Deposited: 18 Jun 2021 15:04
Last Modified: 18 Jun 2021 15:15
URI: http://repository.essex.ac.uk/id/eprint/26711

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