Biomaterial Database

S6 kinase in quiescent Swiss mouse 3T3 cells is activated by phosphorylation in response to serum treatment. 1988

L M Ballou, and M Siegmann, and G Thomas

Friedrich Miescher-Institut, Basel, Switzerland.

To investigate the role of phosphorylation in the activation of S6 kinase, the enzyme was isolated from 32P-labeled Swiss mouse 3T3 cells before and after stimulation with serum. The kinase activity was followed through several purification steps, and a radioactive protein of Mr 70,000 was obtained from the stimulated cells. This band was not detected in resting cells. The Mr 70,000 protein exhibited the same size upon NaDodSO4/PAGE as the homogeneous kinase, and it comigrated with the in vitro autophosphorylated form of the enzyme. Treatment of the in vivo-labeled material with phosphatase 2A led to a loss of kinase activity concomitant with a release of 32Pi from the Mr 70,000 protein. The partially dephosphorylated protein migrated faster during PAGE, displaying distinct species of Mr 69,000 and 68,000. Most importantly, phospho amino acid analysis of the labeled S6 kinase showed only phosphoserine and phosphothreonine. These results argue that the S6 kinase is phosphorylated at multiple sites in vivo and that it is activated by serine/threonine phosphorylation.

UI	MeSH Term	Description	Entries
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D010749	Phosphoprotein Phosphatases	A group of enzymes removing the SERINE- or THREONINE-bound phosphate groups from a wide range of phosphoproteins, including a number of enzymes which have been phosphorylated under the action of a kinase. (Enzyme Nomenclature, 1992)	Phosphoprotein Phosphatase,Phosphoprotein Phosphohydrolase,Protein Phosphatase,Protein Phosphatases,Casein Phosphatase,Ecto-Phosphoprotein Phosphatase,Nuclear Protein Phosphatase,Phosphohistone Phosphatase,Phosphoprotein Phosphatase-2C,Phosphoseryl-Protein Phosphatase,Protein Phosphatase C,Protein Phosphatase C-I,Protein Phosphatase C-II,Protein Phosphatase H-II,Protein-Serine-Threonine Phosphatase,Protein-Threonine Phosphatase,Serine-Threonine Phosphatase,Threonine Phosphatase,Ecto Phosphoprotein Phosphatase,Phosphatase C, Protein,Phosphatase C-I, Protein,Phosphatase C-II, Protein,Phosphatase H-II, Protein,Phosphatase, Casein,Phosphatase, Ecto-Phosphoprotein,Phosphatase, Nuclear Protein,Phosphatase, Phosphohistone,Phosphatase, Phosphoprotein,Phosphatase, Phosphoseryl-Protein,Phosphatase, Protein,Phosphatase, Protein-Serine-Threonine,Phosphatase, Protein-Threonine,Phosphatase, Serine-Threonine,Phosphatase, Threonine,Phosphatase-2C, Phosphoprotein,Phosphatases, Phosphoprotein,Phosphatases, Protein,Phosphohydrolase, Phosphoprotein,Phosphoprotein Phosphatase 2C,Phosphoseryl Protein Phosphatase,Protein Phosphatase C I,Protein Phosphatase C II,Protein Phosphatase H II,Protein Phosphatase, Nuclear,Protein Serine Threonine Phosphatase,Protein Threonine Phosphatase,Serine Threonine Phosphatase
D010766	Phosphorylation	The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.	Phosphorylations
D011494	Protein Kinases	A family of enzymes that catalyze the conversion of ATP and a protein to ADP and a phosphoprotein.	Protein Kinase,Kinase, Protein,Kinases, Protein
D001769	Blood	The body fluid that circulates in the vascular system (BLOOD VESSELS). Whole blood includes PLASMA and BLOOD CELLS.
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D051379	Mice	The common name for the genus Mus.	Mice, House,Mus,Mus musculus,Mice, Laboratory,Mouse,Mouse, House,Mouse, Laboratory,Mouse, Swiss,Mus domesticus,Mus musculus domesticus,Swiss Mice,House Mice,House Mouse,Laboratory Mice,Laboratory Mouse,Mice, Swiss,Swiss Mouse,domesticus, Mus musculus
D054648	Protein Phosphatase 2	A phosphoprotein phosphatase subtype that is comprised of a catalytic subunit and two different regulatory subunits. At least two genes encode isoforms of the protein phosphatase catalytic subunit, while several isoforms of regulatory subunits exist due to the presence of multiple genes and the alternative splicing of their mRNAs. Protein phosphatase 2 acts on a broad variety of cellular proteins and may play a role as a regulator of intracellular signaling processes.	PPP2CA Phosphatase,PPP2CB Phosphatase,Protein Phosphatase 2, Catalytic Subunit,Protein Phosphatase 2, Catalytic Subunit, alpha Isoform,Protein Phosphatase 2, Catalytic Subunit, beta Isoform,Protein Phosphatase 2, Regulatory Subunit,Protein Phosphatase 2, Regulatory Subunit A, alpha Isoform,Protein Phosphatase 2, Regulatory Subunit A, beta Isoform,Protein Phosphatase 2, Regulatory Subunit B, alpha Isoform,Protein Phosphatase 2, Regulatory Subunit B, beta Isoform,Protein Phosphatase 2, Regulatory Subunit B, delta Isoform,Protein Phosphatase 2, Regulatory Subunit B, gamma Isoform,Protein Phosphatase 2A, Catalytic Subunit, alpha Isoform,Protein Phosphatase 2A, Catalytic Subunit, beta Isoform,Protein Phosphatase 2A, Regulatory Subunit A , alpha Isoform,Protein Phosphatase 2A, Regulatory Subunit A, beta Isoform,Protein Phosphatase 2A, Regulatory Subunit B, alpha Isoform,Protein Phosphatase 2A, Regulatory Subunit B, beta Isoform,Protein Phosphatase 2A, Regulatory Subunit B, delta Isoform,Protein Phosphatase 2A, Regulatory Subunit B, gamma Isoform,Protein Phosphatase-2A,Serine Threonine Protein Phosphatase 2A Catalytic Subunit beta Isoform,Serine-Threonine-Protein Phosphatase 2A Catalytic Subunit alpha Isoform,Phosphatase, PPP2CA,Phosphatase, PPP2CB,Protein Phosphatase 2A,Serine Threonine Protein Phosphatase 2A Catalytic Subunit alpha Isoform
D019893	Ribosomal Protein S6 Kinases	A family of protein serine/threonine kinases which act as intracellular signalling intermediates. Ribosomal protein S6 kinases are activated through phosphorylation in response to a variety of HORMONES and INTERCELLULAR SIGNALING PEPTIDES AND PROTEINS. Phosphorylation of RIBOSOMAL PROTEIN S6 by enzymes in this class results in increased expression of 5' top MRNAs. Although specific for RIBOSOMAL PROTEIN S6 members of this class of kinases can act on a number of substrates within the cell. The immunosuppressant SIROLIMUS inhibits the activation of ribosomal protein S6 kinases.	S6 Kinase,Ribosomal Protein S6 Kinase,S6-H4 Kinase,S6 H4 Kinase