Glycogen Synthase Kinase3 Beta Phosphorylates Serine 33 of p53 and Activates p53's Transcriptional Activity

Background: The p53 protein is activated by genotoxic stress, oncogene expression and during senescence, p53 transcriptionally activates genes involved in growth arrest and apoptosis. p53 activation is regulated by post-translational modification, including phosphorylation of the N-terminal transactivation domain. Here, we have examined how Glycogen Synthase Kinase (GSK3), a protein kinase involved in tumorigenesis, differentiation and apoptosis, phosphorylates and regulates p53. Results: The 2 isoforms of GSK3, GSK3α and GSK3β, phosphorylate the sequence Ser-X-X-X-Ser(P) when the C-terminal serine residue is already phosphorylated. Several p53 kinases were examined for their ability to create GSK3 phosphorylation sites on the p53 protein. Our results demonstrate that phosphorylation of serine 37 of p53 by DNA-PK creates a site for GSK3β phosphorylation at serine 33 in vitro. GSK3α did not phosphorylate p53 under any condition. GSK3β increased the transcriptional activity of the p53 protein in vivo. Mutation of either serine 33 or serine 37 of p53 to alanine blocked the ability of GSK3β to regulate p53 transcriptional activity. GSK3β is therefore able to regulate p53 function in vivo. p53's transcriptional activity is commonly increased by DNA damage. However, GSK3β kinase activity was inhibited in response to DNA damage, suggesting that GSK3β regulation of p53 is not involved in the p53-DNA damage response. Conclusions: GSK3β can regulate p53's transcriptional activity by phosphorylating serine 33. However, GSK3β does not appear to be part of the p53-DNA damage response pathway. Instead, GSK3β may provide the link between p53 and non-DNA damage mechanisms for p53 activation

Glycogen synthase kinase3 beta phosphorylates serine 33 of p53 and activates p53's transcriptional activity

BACKGROUND: The p53 protein is activated by genotoxic stress, oncogene expression and during senescence, p53 transcriptionally activates genes involved in growth arrest and apoptosis. p53 activation is regulated by post-translational modification, including phosphorylation of the N-terminal transactivation domain. Here, we have examined how Glycogen Synthase Kinase (GSK3), a protein kinase involved in tumorigenesis, differentiation and apoptosis, phosphorylates and regulates p53. RESULTS: The 2 isoforms of GSK3, GSK3α and GSK3β, phosphorylate the sequence Ser-X-X-X-Ser(P) when the C-terminal serine residue is already phosphorylated. Several p53 kinases were examined for their ability to create GSK3 phosphorylation sites on the p53 protein. Our results demonstrate that phosphorylation of serine 37 of p53 by DNA-PK creates a site for GSK3β phosphorylation at serine 33 in vitro. GSK3α did not phosphorylate p53 under any condition. GSK3β increased the transcriptional activity of the p53 protein in vivo. Mutation of either serine 33 or serine 37 of p53 to alanine blocked the ability of GSK3β to regulate p53 transcriptional activity. GSK3β is therefore able to regulate p53 function in vivo. p53's transcriptional activity is commonly increased by DNA damage. However, GSK3β kinase activity was inhibited in response to DNA damage, suggesting that GSK3β regulation of p53 is not involved in the p53-DNA damage response. CONCLUSIONS: GSK3β can regulate p53's transcriptional activity by phosphorylating serine 33. However, GSK3β does not appear to be part of the p53-DNA damage response pathway. Instead, GSK3β may provide the link between p53 and non-DNA damage mechanisms for p53 activation

Buffet-Onset Constraint Formulation for Aerodynamic Shape Optimization

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143072/1/1.J055172.pd

Multipoint Aerodynamic Shape Optimization Investigations of the Common Research Model Wing

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140687/1/1.J054154.pd

Aerostructural Optimization of the D8 Wing with Varying Cruise Mach Numbers

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143079/1/6.2017-4436.pd

The lipid environment determines the activity of the Escherichia coli ammonium transporter AmtB

The movement of ammonium across biologic membranes is a fundamental process in all living organ-isms and is mediated by the ubiquitous ammonium transporter/methylammonium permease/rhesus protein (Amt/Mep/Rh) family of transporters. Recent structural analysis and coupled mass spectrometry studies have shown that the Escherichia coli ammonium transporter AmtB specifically binds 1-palmitoyl-2-oleoyl phosphatidylglycerol (POPG). Upon POPG binding, several residues of AmtB undergo a small conformational change, which stabilizes the protein against unfolding. However, no studies have so far been conducted, to our knowledge, to explore whether POPG binding to AmtB has functional consequences. Here, we used an in vitro experimental assay with purified components, together with molecular dynamics simulations, to characterize the relation between POPG binding and AmtB activity. We show that the AmtB activity is electrogenic. Our results indicate that the activity, at the molecular level, of Amt in archaebacteria and eubacteria may differ. We also show that POPG is an important cofactor for AmtB activity and that, in the absence of POPG, AmtB cannot complete the full translocation cycle. Furthermore, our simulations reveal previously undiscovered POPG binding sites on the intracellular side of the lipid bilayer between the AmtB subunits. Possible molecular mechanisms explaining the functional role of POPG are discussed

Aerodynamic Shape Optimization Investigations of the Common Research Model Wing Benchmark

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140684/1/1.J053318.pd

Multimission Aircraft Fuel-Burn Minimization via Multipoint Aerostructural Optimization

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140677/1/1.J052940.pd

Modeling Boundary Layer Ingestion Using a Coupled Aeropropulsive Analysis

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143109/1/1.C034601.pd

Scalable Parallel Approach for High-Fidelity Steady-State Aeroelastic Analysis and Adjoint Derivative Computations

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140671/1/1.j052255.pd