Linked Life Data

12023960

Source:http://linkedlifedata.com/resource/pubmed/id/12023960

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
31
pubmed:dateCreated
2002-7-29
pubmed:abstractText
The AGC family of protein kinases, which includes isoforms of protein kinase B (also known as Akt), ribosomal S6 protein kinase (S6K), and serum- and glucocorticoid-induced protein kinase (SGK) are activated in response to many extracellular signals and play key roles in regulating diverse cellular processes. They are activated by the phosphorylation of the T loop of their kinase domain by the 3-phosphoinositide-dependent protein kinase-1 and by phosphorylation of a residue located C-terminal to the kinase domain in a region termed the hydrophobic motif. Recent work has implicated the NIMA (never in mitosis, gene A)-related kinase-6 (NEK6) as the enzyme that phosphorylates the hydrophobic motif of S6K1 in vivo. Here we demonstrate that in addition to phosphorylating S6K1 and SGK1 at their hydrophobic motif, NEK6 also phosphorylates S6K1 at two other sites and phosphorylates SGK1 at one other site in vitro. Employing the Jerini pepSTAR method in combination with kinetic analysis of phosphorylation of variant peptides, we establish the key substrate specificity determinants for NEK6. Our analysis indicates that NEK6 has a strong preference for Leu 3 residues N-terminal to the site of phosphorylation. Its mutation to either Ile or Val severely reduced the efficacy with which NEK6-phosphorylated peptide substrates, and moreover, mutation of the equivalent Leu residue in S6K1 or SGK1 prevented phosphorylation of their hydrophobic motifs by NEK6 in vitro. However, these mutants of S6K1 or SGK1 still became phosphorylated at their hydrophobic motif following insulin-like growth factor-1 stimulation of transfected 293 cells. This study provides the first description of the basis for the substrate specificity of NEK6 and indicates that NEK6 is unlikely to be responsible for the IGF1-induced phosphorylation of the hydrophobic motif of S6K, SGK, and protein kinase B isoforms in vivo.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
2
pubmed:volume
277
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
27839-49
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed-meshheading:12023960-Amino Acid Sequence, pubmed-meshheading:12023960-Base Sequence, pubmed-meshheading:12023960-Cloning, Molecular, pubmed-meshheading:12023960-DNA Primers, pubmed-meshheading:12023960-Enzyme Activation, pubmed-meshheading:12023960-Glucocorticoids, pubmed-meshheading:12023960-Humans, pubmed-meshheading:12023960-Kinetics, pubmed-meshheading:12023960-Molecular Sequence Data, pubmed-meshheading:12023960-Peptide Fragments, pubmed-meshheading:12023960-Peptide Mapping, pubmed-meshheading:12023960-Phosphorylation, pubmed-meshheading:12023960-Protein Kinases, pubmed-meshheading:12023960-Protein-Serine-Threonine Kinases, pubmed-meshheading:12023960-Proto-Oncogene Proteins, pubmed-meshheading:12023960-Proto-Oncogene Proteins c-akt, pubmed-meshheading:12023960-Ribosomal Protein S6 Kinases, pubmed-meshheading:12023960-Substrate Specificity
pubmed:year
2002
pubmed:articleTitle
Molecular basis for the substrate specificity of NIMA-related kinase-6 (NEK6). Evidence that NEK6 does not phosphorylate the hydrophobic motif of ribosomal S6 protein kinase and serum- and glucocorticoid-induced protein kinase in vivo.
pubmed:affiliation
Medical Research Council Protein Phosphorylation Unit, University of Dundee, Dow Street, Dundee DD1 5EH, Scotland, United Kingdom. j.m.lizcano@dundee.ac.uk
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't