scholarly journals Erk1/2 Inactivation-Induced c-Jun Degradation Is Regulated by Protein Phosphatases, UBE2d3, and the C-Terminus of c-Jun

2021 ◽  
Vol 22 (8) ◽  
pp. 3889
Author(s):  
Weiming Ouyang ◽  
David M. Frucht
Keyword(s):  
Protein Degradation ◽  
Protein Phosphatase ◽  
Protein Phosphatases ◽  
Degradation Pathway ◽  
Protein Phosphatase 1 ◽  
Amino Acid Residues ◽  
Ubiquitin E3 Ligase ◽  
C Terminus ◽  
Or Gene ◽  
E2 Enzymes

Constitutive photomorphogenic 1 (COP1) is the ubiquitin E3 ligase that mediates degradation of c-Jun protein upon Erk1/2 inactivation. It remains unknown how this protein degradation pathway is regulated. In this study, we investigated the roles of protein phosphatases, ubiquitin-conjugating E2 enzymes (UBE2), and an intrinsic motif of c-Jun in regulating this degradation pathway. By using pharmacological inhibitors and/or gene knockdown techniques, we identified protein phosphatase 1 (PP1) and PP2A as the phosphatases and UBE23d as the UBE2 promoting c-Jun degradation, triggered by Erk1/2 inactivation. In addition, we report that the C-terminus of c-Jun protein facilitates its degradation. The addition of a C-terminal tag or deletion of the last four amino acid residues from the C-terminus of c-Jun protects it from degradation under Erk1/2-inactivating conditions. Taken together, this study reveals that the Erk1/2 inactivation-triggered and COP1-mediated c-Jun degradation is extrinsically and intrinsically regulated, providing a new understanding of the mechanisms underlying this protein degradation pathway.

scholarly journals Identification of Novel Serine/Threonine Protein Phosphatases inTrypanosoma cruzi: a Potential Role in Control of Cytokinesis and Morphology

2000 ◽  
Vol 68 (3) ◽  
pp. 1350-1358 ◽  
Author(s):  
George A. Orr ◽  
Craig Werner ◽  
Jun Xu ◽  
Marcia Bennett ◽  
Louis M. Weiss ◽  
...  
Keyword(s):  
Cell Division ◽  
Okadaic Acid ◽  
Blot Analysis ◽  
Protein Phosphatase ◽  
Protein Phosphatases ◽  
Growth Arrest ◽  
Human Protein ◽  
Protein Phosphatase 1 ◽  
Calyculin A ◽  
Metacyclic Trypomastigote

ABSTRACT We cloned two novel Trypanosoma cruzi proteins by using degenerate oligonucleotide primers prepared against conserved domains in mammalian serine/threonine protein phosphatases 1, 2A, and 2B. The isolated genes encoded proteins of 323 and 330 amino acids, respectively, that were more homologous to the catalytic subunit of human protein phosphatase 1 than to those of human protein phosphatase 2A or 2B. The proteins encoded by these genes have been tentatively designated TcPP1α and TcPP1β. Northern blot analysis revealed the presence of a major 2.3-kb mRNA transcript hybridizing to each gene in both the epimastigote and metacyclic trypomastigote developmental stages. Southern blot analysis suggests that each protein phosphatase 1 gene is present as a single copy in the T. cruzi genome. The complete coding region for TcPP1β was expressed inEscherichia coli by using a vector, pTACTAC, with thetrp-lac hybrid promoter. The recombinant protein from the TcPP1β construct displayed phosphatase activity toward phosphorylasea, and this activity was preferentially inhibited by calyculin A (50% inhibitory concentration [IC50], ∼2 nM) over okadaic acid (IC50, ∼100 nM). Calyculin A, but not okadaic acid, had profound effects on the in vitro replication and morphology of T. cruzi epimastigotes. Low concentrations of calyculin A (1 to 10 nM) caused growth arrest. Electron microscopic studies of the calyculin A-treated epimastigotes revealed that the organisms underwent duplication of organelles, including the flagellum, kinetoplast, and nucleus, but were incapable of completing cell division. At concentrations higher than 10 nM, or upon prolonged incubation at lower concentrations, the epimastigotes lost their characteristic elongated spindle shape and had a more rounded morphology. Okadaic acid at concentrations up to 1 μM did not result in growth arrest or morphological alterations to T. cruziepimastigotes. Calyculin A, but not okadaic acid, was also a potent inhibitor of the dephosphorylation of 32P-labeled phosphorylase a by T. cruzi epimastigotes and metacyclic trypomastigote extracts. These inhibitor studies suggest that in T. cruzi, type 1 protein phosphatases are important for the completion of cell division and for the maintenance of cell shape.

scholarly journals Tyr306 near the C-terminus of protein phosphatase-1 affects enzyme stability and inhibitor binding

IUBMB Life ◽  
2011 ◽  
Vol 63 (7) ◽  
pp. 574-581
Author(s):  
Bai J. Wang ◽  
Wei Tang ◽  
Peng Zhang ◽  
Qun Wei
Keyword(s):  
Protein Phosphatase ◽  
Enzyme Stability ◽  
Protein Phosphatase 1 ◽  
Inhibitor Binding ◽  
C Terminus

scholarly journals The Inhibitor-1 C Terminus Facilitates Hormonal Regulation of Cellular Protein Phosphatase-1

2004 ◽  
Vol 279 (47) ◽  
pp. 48904-48914 ◽  
Author(s):  
Douglas C. Weiser ◽  
Suzanne Sikes ◽  
Shi Li ◽  
Shirish Shenolikar
Keyword(s):  
Protein Phosphatase ◽  
Hormonal Regulation ◽  
Cellular Protein ◽  
Protein Phosphatase 1 ◽  
C Terminus

scholarly journals Blocking Protein Phosphatase 1 [PP1] Prevents Loss of Tether Elasticity in Anaphase Crane-Fly Spermatocytes

2021 ◽  
Vol 8 ◽  
Author(s):  
Arthur Forer ◽  
Aisha Adil ◽  
Michael W. Berns
Keyword(s):  
Protein Phosphatase ◽  
Chromosome Pair ◽  
Protein Phosphatases ◽  
Protein Phosphatase 1 ◽  
Calyculin A ◽  
Early Anaphase ◽  
In Cells

In normal anaphase cells, telomeres of each separating chromosome pair are connected to each other by tethers. Tethers are elastic at the start of anaphase: arm fragments cut from anaphase chromosomes in early anaphase move across the equator to the oppositely-moving chromosome, telomere moving toward telomere. Tethers become inelastic later in anaphase as the tethers become longer: arm fragments no longer move to their partners. When early anaphase cells are treated with Calyculin A (CalA), an inhibitor of protein phosphatases 1 (PP1) and 2A (PP2A), at the end of anaphase chromosomes move backward from the poles, with telomeres moving toward partner telomeres. Experiments described herein show that in cells treated with CalA, backwards movements are stopped in a variety of ways, by cutting the tethers of backwards moving chromosomes, by severing arms of backwards moving chromosomes, by severing arms before the chromosomes reach the poles, and by cutting the telomere toward which a chromosome is moving backwards. Measurements of arm-fragment velocities show that CalA prevents tethers from becoming inelastic as they lengthen. Since treatment with CalA causes tethers to remain elastic throughout anaphase and since inhibitors of PP2A do not cause the backwards movements, PP1 activity during anaphase causes the tethers to become inelastic.

scholarly journals Identification of the separate domains in the hepatic glycogen-targeting subunit of protein phosphatase 1 that interact with phosphorylase a, glycogen and protein phosphatase 1

1998 ◽  
Vol 336 (3) ◽  
pp. 699-704 ◽  
Author(s):  
Christopher G. ARMSTRONG ◽  
Martin J. DOHERTY ◽  
Patricia T. W. COHEN
Keyword(s):  
Protein Phosphatase ◽  
Glycogen Synthesis ◽  
Liver Glycogen ◽  
Binding Domain ◽  
Protein Phosphatase 1 ◽  
Hepatic Glycogen ◽  
Storage Site ◽  
C Terminus ◽  
Lysine Residues ◽  
High Affinity Binding Site

Deletion and mutational analyses of the rat liver glycogen-targeting subunit (GL) of protein phosphatase 1 (PP1) have identified three separate domains that are responsible for binding of PP1, glycogen and phosphorylase a. The glycogen-binding domain spans the centre of GL between residues 144 and 231 and appears to be distinct from the glycogen-binding (storage) site of phosphorylase. The regulatory high-affinity binding site for phosphorylase a lies in the 16 amino acids at the C-terminus of GL. The PP1-binding domain is deduced to comprise the -RVXF- motif [Egloff, Johnson, Moorhead, Cohen and Barford (1997) EMBO J. 16, 1876–1887] located at residues 61–64 of GL and preceding lysine residues at positions 56, 57 and 59. A possible approach for increasing glycogen synthesis in certain disorders is discussed.

scholarly journals The C-terminus of NIPP1 (nuclear inhibitor of protein phosphatase-1) contains a novel binding site for protein phosphatase-1 that is controlled by tyrosine phosphorylation and RNA binding

2000 ◽  
Vol 352 (3) ◽  
pp. 651-658 ◽  
Author(s):  
Monique BEULLENS ◽  
Veerle VULSTEKE ◽  
Aleyde VAN EYNDE ◽  
Izabela JAGIELLO ◽  
Willy STALMANS ◽  
...  
Keyword(s):  
Binding Site ◽  
Protein Phosphatase ◽  
Rna Binding ◽  
Protein Phosphatase 1 ◽  
Regulatory Subunits ◽  
Site Model ◽  
Interaction Sites ◽  
Binding Domains ◽  
C Terminus ◽  
Terminal Site

Nuclear inhibitor of protein phosphatase-1 (NIPP1; 351 residues) is a nuclear RNA-binding protein that also contains in its central domain two contiguous sites of interaction with the catalytic subunit of protein phosphatase-1 (PP1C). We show here that mutation of these phosphatase-interaction sites did not completely abolish the ability of NIPP1 to bind and inhibit PP1C. This could be accounted for by an additional inhibitory phosphatase-binding site in the C-terminal region (residues 311Ő351), with an inhibitory core corresponding to residues 331Ő337. Following mutation of all three PP1C-binding sites in the central and C-terminal domains, NIPP1 no longer interacted with PP1C. Remarkably, while both NIPP1 domains inhibited the phosphorylase phosphatase activity of PP1C independently, mutation of either domain completely abolished the ability of NIPP1 to inhibit the dephosphorylation of myelin basic protein. The inhibitory potency of the C-terminal site of NIPP1 was decreased by phosphorylation of Tyr-335 and by the addition of RNA. Tyr-335 could be phosphorylated by tyrosine kinase Lyn, but only in the presence of RNA. In conclusion, NIPP1 contains two phosphatase-binding domains that function co-operatively but which are controlled independently. Our data are in agreement with a shared-site model for the interaction of PP1C with its regulatory subunits.

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