Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Compartmentalized phosphorylation of IAP by protein kinase A regulates cytoprotection.

ABSTRACT: Cell death pathways are likely regulated in specialized subcellular microdomains, but how this occurs is not understood. Here, we show that cyclic AMP-dependent protein kinase A (PKA) phosphorylates the inhibitor of apoptosis (IAP) protein survivin on Ser20 in the cytosol, but not in mitochondria. This phosphorylation event disrupts the binding interface between survivin and its antiapoptotic cofactor, XIAP. Conversely, mitochondrial survivin or a non-PKA phosphorylatable survivin mutant binds XIAP avidly, enhances XIAP stability, synergistically inhibits apoptosis, and accelerates tumor growth, in vivo. Therefore, differential phosphorylation of survivin by PKA in subcellular microdomains regulates tumor cell apoptosis via its interaction with XIAP.

SUBMITTER: Dohi T

PROVIDER: S-EPMC1986705 | biostudies-literature | 2007 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Compartmentalized phosphorylation of IAP by protein kinase A regulates cytoprotection.

Dohi Takehiko T Xia Fang F Altieri Dario C DC

Molecular cell 20070701 1

Cell death pathways are likely regulated in specialized subcellular microdomains, but how this occurs is not understood. Here, we show that cyclic AMP-dependent protein kinase A (PKA) phosphorylates the inhibitor of apoptosis (IAP) protein survivin on Ser20 in the cytosol, but not in mitochondria. This phosphorylation event disrupts the binding interface between survivin and its antiapoptotic cofactor, XIAP. Conversely, mitochondrial survivin or a non-PKA phosphorylatable survivin mutant binds X ...[more]

PMID: 17612487

Similar Datasets

Phosphorylation of the compartmentalized PKA substrate TAF15 regulates RNA-protein interactions.

Project description:Spatiotemporal-controlled second messengers alter molecular interactions of central signaling nodes for ensuring physiological signal transmission. One prototypical second messenger molecule which modulates kinase signal transmission is the cyclic-adenosine monophosphate (cAMP). The main proteinogenic cellular effectors of cAMP are compartmentalized protein kinase A (PKA) complexes. Their cell-type specific compositions precisely coordinate substrate phosphorylation and proper signal propagation which is indispensable for numerous cell-type specific functions. Here we present evidence that TAF15, which is implicated in the etiology of amyotrophic lateral sclerosis, represents a novel nuclear PKA substrate. In cross-linking and immunoprecipitation experiments (iCLIP) we showed that TAF15 phosphorylation alters the binding to target transcripts related to mRNA maturation, splicing and protein-binding related functions. TAF15 appears to be one of multiple PKA substrates that undergo RNA-binding dynamics upon phosphorylation. We observed that the activation of the cAMP-PKA signaling axis caused a change in the composition of a collection of RNA species that interact with TAF15. This observation appears to be a broader principle in the regulation of molecular interactions, as we identified a significant enrichment of RNA-binding proteins within endogenous PKA complexes. We assume that phosphorylation of RNA-binding domains adds another layer of regulation to binary protein-RNAs interactions with consequences to RNA features including binding specificities, localization, abundance and composition.

| S-EPMC10991009 | biostudies-literature

Adapter protein Shc regulates Janus kinase 3 phosphorylation.

Project description:Although constitutive activation of Janus kinase 3 (Jak3) leads to different cancers, the mechanism of trans-molecular regulation of Jak3 activation is not known. Previously we reported that Jak3 interactions with adapter protein p52ShcA (Shc) facilitate mucosal homeostasis. In this study, we characterize the structural determinants that regulate the interactions between Jak3 and Shc and demonstrate the trans-molecular mechanism of regulation of Jak3 activation by Shc. We show that Jak3 autophosphorylation was the rate-limiting step during Jak3 trans-phosphorylation of Shc where Jak3 directly phosphorylated two tyrosine residues in Src homology 2 (SH2) domain and one tyrosine residue each in calponin homology 1 (CH1) domain and phosphotyrosine interaction domain (PID) of Shc. Direct interactions between mutants of Jak3 and Shc showed that although FERM domain of Jak3 was sufficient for binding to Shc, CH1 and PID domains of Shc were responsible for binding to Jak3. Functionally Jak3 was autophosphorylated under IL-2 stimulation in epithelial cells. However, Shc recruited tyrosine phosphatases SHP2 and PTP1B to Jak3 and thereby dephosphorylated Jak3. Thus we not only characterize Jak3 interaction with Shc, but also demonstrate the molecular mechanism of intracellular regulation of Jak3 activation where Jak3 interactions with Shc acted as regulators of Jak3 dephosphorylation through direct interactions of Shc with both Jak3 and tyrosine phosphatases.

| S-EPMC4047368 | biostudies-literature

A secretory kinase complex regulates extracellular protein phosphorylation.

Project description:Although numerous extracellular phosphoproteins have been identified, the protein kinases within the secretory pathway have only recently been discovered, and their regulation is virtually unexplored. Fam20C is the physiological Golgi casein kinase, which phosphorylates many secreted proteins and is critical for proper biomineralization. Fam20A, a Fam20C paralog, is essential for enamel formation, but the biochemical function of Fam20A is unknown. Here we show that Fam20A potentiates Fam20C kinase activity and promotes the phosphorylation of enamel matrix proteins in vitro and in cells. Mechanistically, Fam20A is a pseudokinase that forms a functional complex with Fam20C, and this complex enhances extracellular protein phosphorylation within the secretory pathway. Our findings shed light on the molecular mechanism by which Fam20C and Fam20A collaborate to control enamel formation, and provide the first insight into the regulation of secretory pathway phosphorylation.

| S-EPMC4421793 | biostudies-literature

Phosphorylation of Dishevelled by protein kinase RIPK4 regulates Wnt signaling.

Project description:Receptor-interacting protein kinase 4 (RIPK4) is required for epidermal differentiation and is mutated in Bartsocas-Papas syndrome. RIPK4 binds to protein kinase C, but its signaling mechanisms are largely unknown. Ectopic RIPK4, but not catalytically inactive or Bartsocas-Papas RIPK4 mutants, induced accumulation of cytosolic ?-catenin and a transcriptional program similar to that caused by Wnt3a. In Xenopus embryos, Ripk4 synergized with coexpressed Xwnt8, whereas Ripk4 morpholinos or catalytic inactive Ripk4 antagonized Wnt signaling. RIPK4 interacted constitutively with the adaptor protein DVL2 and, after Wnt3a stimulation, with the co-receptor LRP6. Phosphorylation of DVL2 by RIPK4 favored canonical Wnt signaling. Wnt-dependent growth of xenografted human tumor cells was suppressed by RIPK4 knockdown, suggesting that RIPK4 overexpression may contribute to the growth of certain tumor types.

| S-EPMC4094295 | biostudies-literature

A compartmentalized phosphorylation/dephosphorylation system that regulates U snRNA export from the nucleus.

Project description:PHAX (phosphorylated adaptor for RNA export) is the key regulator of U snRNA nuclear export in metazoa. Our previous work revealed that PHAX is phosphorylated in the nucleus and is exported as a component of the U snRNA export complex to the cytoplasm, where it is dephosphorylated (M. Ohno, A. Segref, A. Bachi, M. Wilm, and I. W. Mattaj, Cell 101:187-198, 2000). PHAX phosphorylation is essential for export complex assembly, whereas its dephosphorylation causes export complex disassembly. Thus, PHAX is subject to a compartmentalized phosphorylation/dephosphorylation cycle that contributes to transport directionality. However, neither essential PHAX phosphorylation sites nor the modifying enzymes that contribute to the compartmentalized system have been identified. Here, we identify PHAX phosphorylation sites that are necessary and sufficient for U snRNA export. Mutation of the phosphorylation sites inhibited U snRNA export in a dominant-negative way. We also show, by both biochemical and RNA interference knockdown experiments, that the nuclear kinase and the cytoplasmic phosphatase for PHAX are CK2 kinase and protein phosphatase 2A, respectively. Our results reveal the composition of the compartmentalized phosphorylation/dephosphorylation system that regulates U snRNA export. This finding was surprising in that such a specific system for U snRNA export regulation is composed of two such universal regulators, suggesting that this compartmentalized system is used more broadly for gene expression regulation.

| S-EPMC2223276 | biostudies-literature

Protein kinase D-mediated phosphorylation at Ser99 regulates localization of p21-activated kinase 4.

Project description:PAKs (p21-activated kinases) are effectors of RhoGTPases. PAK4 contributes to regulation of cofilin at the leading edge of migrating cells through activation of LIMK (Lin-11/Isl-1/Mec-3 kinase). PAK4 activity is regulated by an autoinhibitory domain that is released upon RhoGTPase binding as well as phosphorylation at Ser474 in the activation loop of the kinase domain. In the present study, we add another level of complexity to PAK4 regulation by showing that phosphorylation at Ser99 is required for its targeting to the leading edge. This phosphorylation is mediated by PKD1 (protein kinase D1). Phosphorylation of PAK4 at Ser99 also mediates binding to 14-3-3 protein, and is required for the formation of a PAK4-LIMK-PKD1 complex that regulates cofilin activity and directed cell migration.

| S-EPMC3880571 | biostudies-literature

Constitutive phosphorylation by protein kinase C regulates D1 dopamine receptor signaling.

Project description:The D(1) dopamine receptor (D(1) DAR) is robustly phosphorylated by multiple protein kinases, yet the phosphorylation sites and functional consequences of these modifications are not fully understood. Here, we report that the D(1) DAR is phosphorylated by protein kinase C (PKC) in the absence of agonist stimulation. Phosphorylation of the D(1) DAR by PKC is constitutive in nature, can be induced by phorbol ester treatment or through activation of Gq-mediated signal transduction pathways, and is abolished by PKC inhibitors. We demonstrate that most, but not all, isoforms of PKC are capable of phosphorylating the receptor. To directly assess the functional role of PKC phosphorylation of the D(1) DAR, a site-directed mutagenesis approach was used to identify the PKC sites within the receptor. Five serine residues were found to mediate the PKC phosphorylation. Replacement of these residues had no effect on D(1) DAR expression or agonist-induced desensitization; however, G protein coupling and cAMP accumulation were significantly enhanced in PKC-null D(1) DAR. Thus, constitutive or heterologous PKC phosphorylation of the D(1) DAR dampens dopamine activation of the receptor, most likely occurring in a context-specific manner, mediated by the repertoire of PKC isozymes within the cell.

| S-EPMC2996484 | biostudies-literature

Casein kinase 2 regulates telomere protein complex formation through Rap1 phosphorylation.

Project description:Telomeres located at the ends of linear chromosomes play important roles in the maintenance of life. Rap1, a component of the shelterin telomere protein complex, interacts with multiple proteins to perform various functions; further, formation of shelterin requires Rap1 binding to other components such as Taz1 and Poz1, and telomere tethering to the nuclear envelope (NE) involves interactions between Rap1 and Bqt4, a nuclear membrane protein. Although Rap1 is a hub for telomere protein complexes, the regulatory mechanisms of its interactions with partner proteins are not fully understood. Here, we show that Rap1 is phosphorylated by casein kinase 2 (CK2) at multiple sites, which promotes interactions with Bqt4 and Poz1. Among the multiple CK2-mediated phosphorylation sites of Rap1, phosphorylation at Ser496 was found to be crucial for both Rap1-Bqt4 and Rap1-Poz1 interactions. These mechanisms mediate proper telomere tethering to the NE and the formation of the silenced chromatin structure at chromosome ends.

| S-EPMC6648331 | biostudies-literature

Protein kinase A-mediated phosphorylation regulates STAT3 activation and oncogenic EZH2 activity

Project description:The effect of T372E-EZH2 and Wt-EZH2 overexpression on gene expression in TOV112D cells. We found in this study that Protein Kinase A phosphorylates T372-EZH2 and wanted to determine the gene expression changes brought upon this phosphorylation. We made a point mutation (T372E) that mimicked phospho T372-EZH2. The objective was to observe transcriptional changes in TOV112D cells in response to ectopic expression of Wt-EZH2 and T372E-EZH2 point mutation in TOV112D cells.

2018-06-05 | GSE108418 | GEO