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Mandal AK, Leask MP, Sumpter NA, Choi HK, Merriman TR, Mount DB. Genetic and Physiological Effects of Insulin-Like Growth Factor-1 (IGF-1) on Human Urate Homeostasis. J Am Soc Nephrol 2023; 34:451-466. [PMID: 36735516 PMCID: PMC10103387 DOI: 10.1681/asn.0000000000000054] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 10/25/2022] [Indexed: 01/22/2023] Open
Abstract
SIGNIFICANCE STATEMENT Hyperinsulinemia induces hyperuricemia by activating net renal urate reabsorption in the renal proximal tubule. The basolateral reabsorptive urate transporter GLUT9a appears to be the dominant target for insulin. By contrast, IGF-1 infusion reduces serum urate (SU), through mechanisms unknown. Genetic variants of IGF1R associated with reduced SU have increased IGF-1R expression and interact with genes encoding the GLUT9 and ABCG2 urate transporters, in a sex-specific fashion, which controls the SU level. Activation of IGF-1/IGF-1R signaling in Xenopus oocytes modestly activates GLUT9a and inhibits insulin's stimulatory effect on the transporter, which also activates multiple secretory urate transporters-ABCG2, ABCC4, OAT1, and OAT3. The results collectively suggest that IGF-1 reduces SU by activating secretory urate transporters and inhibiting insulin's action on GLUT9a. BACKGROUND Metabolic syndrome and hyperinsulinemia are associated with hyperuricemia. Insulin infusion in healthy volunteers elevates serum urate (SU) by activating net urate reabsorption in the renal proximal tubule, whereas IGF-1 infusion reduces SU by mechanisms unknown. Variation within the IGF1R gene also affects SU levels. METHODS Colocalization analyses of a SU genome-wide association studies signal at IGF1R and expression quantitative trait loci signals in cis using COLOC2, RT-PCR, Western blotting, and urate transport assays in transfected HEK 293T cells and in Xenopus laevis oocytes. RESULTS Genetic association at IGF1R with SU is stronger in women and is mediated by control of IGF1R expression. Inheritance of the urate-lowering homozygous genotype at the SLC2A9 locus is associated with a differential effect of IGF1R genotype between men and women. IGF-1, through IGF-1R, stimulated urate uptake in human renal proximal tubule epithelial cells and transfected HEK 293T cells, through activation of IRS1, PI3/Akt, MEK/ERK, and p38 MAPK; urate uptake was inhibited in the presence of uricosuric drugs, specific inhibitors of protein tyrosine kinase, PI3 kinase (PI3K), ERK, and p38 MAPK. In X. laevis oocytes expressing ten individual urate transporters, IGF-1 through endogenous IGF-1R stimulated urate transport mediated by GLUT9, OAT1, OAT3, ABCG2, and ABCC4 and inhibited insulin's stimulatory action on GLUT9a and OAT3. IGF-1 significantly activated Akt and ERK. Specific inhibitors of PI3K, ERK, and PKC significantly affected IGF-1 stimulation of urate transport in oocytes. CONCLUSIONS The combined results of infusion, genetics, and transport experiments suggest that IGF-1 reduces SU by activating urate secretory transporters and inhibiting insulin's action.
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Affiliation(s)
- Asim K. Mandal
- Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Megan P. Leask
- Biochemistry Department, University of Otago, Dunedin, South Island, New Zealand
- Division of Rheumatology and Clinical Immunology, University of Alabama, Birmingham, Alabama
| | - Nicholas A. Sumpter
- Division of Rheumatology and Clinical Immunology, University of Alabama, Birmingham, Alabama
| | - Hyon K. Choi
- Division of Rheumatology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Tony R. Merriman
- Biochemistry Department, University of Otago, Dunedin, South Island, New Zealand
- Division of Rheumatology and Clinical Immunology, University of Alabama, Birmingham, Alabama
| | - David B. Mount
- Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
- Renal Division, VA Boston Healthcare System, Harvard Medical School, Boston, Massachusetts
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Mandal AK, Leask MP, Estiverne C, Choi HK, Merriman TR, Mount DB. Genetic and Physiological Effects of Insulin on Human Urate Homeostasis. Front Physiol 2021; 12:713710. [PMID: 34408667 PMCID: PMC8366499 DOI: 10.3389/fphys.2021.713710] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Accepted: 07/02/2021] [Indexed: 12/19/2022] Open
Abstract
Insulin and hyperinsulinemia reduce renal fractional excretion of urate (FeU) and play a key role in the genesis of hyperuricemia and gout, via uncharacterized mechanisms. To explore this association further we studied the effects of genetic variation in insulin-associated pathways on serum urate (SU) levels and the physiological effects of insulin on urate transporters. We found that urate-associated variants in the human insulin (INS), insulin receptor (INSR), and insulin receptor substrate-1 (IRS1) loci associate with the expression of the insulin-like growth factor 2, IRS1, INSR, and ZNF358 genes; additionally, we found genetic interaction between SLC2A9 and the three loci, most evident in women. We also found that insulin stimulates the expression of GLUT9 and increases [14C]-urate uptake in human proximal tubular cells (PTC-05) and HEK293T cells, transport activity that was effectively abrogated by uricosurics or inhibitors of protein tyrosine kinase (PTK), PI3 kinase, MEK/ERK, or p38 MAPK. Heterologous expression of individual urate transporters in Xenopus oocytes revealed that the [14C]-urate transport activities of GLUT9a, GLUT9b, OAT10, OAT3, OAT1, NPT1 and ABCG2 are directly activated by insulin signaling, through PI3 kinase (PI3K)/Akt, MEK/ERK and/or p38 MAPK. Given that the high-capacity urate transporter GLUT9a is the exclusive basolateral exit pathway for reabsorbed urate from the renal proximal tubule into the blood, that insulin stimulates both GLUT9 expression and urate transport activity more than other urate transporters, and that SLC2A9 shows genetic interaction with urate-associated insulin-signaling loci, we postulate that the anti-uricosuric effect of insulin is primarily due to the enhanced expression and activation of GLUT9.
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Affiliation(s)
- Asim K. Mandal
- Renal Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States
| | - Megan P. Leask
- Biochemistry Department, University of Otago, Dunedin, New Zealand
- Division of Rheumatology and Clinical Immunology, University of Alabama, Birmingham, AL, United States
| | - Christopher Estiverne
- Renal Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States
| | - Hyon K. Choi
- Division of Rheumatology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Tony R. Merriman
- Biochemistry Department, University of Otago, Dunedin, New Zealand
- Division of Rheumatology and Clinical Immunology, University of Alabama, Birmingham, AL, United States
| | - David B. Mount
- Renal Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States
- Renal Division, VA Boston Healthcare System, Harvard Medical School, Boston, MA, United States
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3
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Delobel P, Flament S, Hamdane M, Delacourte A, Vilain JP, Buée L. Modelling Alzheimer-specific abnormal Tau phosphorylation independently of GSK3beta and PKA kinase activities. FEBS Lett 2002; 516:151-5. [PMID: 11959122 DOI: 10.1016/s0014-5793(02)02525-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In Alzheimer's disease, neurofibrillary degeneration results from the aggregation of abnormally phosphorylated Tau proteins into paired helical filaments. These Tau variants displayed specific epitopes that are immunoreactive with anti-phospho-Tau antibodies such as AT100. As shown in in vitro experiments, glycogen synthase kinase 3 beta (GSK3beta) and protein kinase A (PKA) may be key kinases in these phosphorylation events. In the present study, Tau was microinjected into Xenopus oocytes. Surprisingly, in this system, AT100 was generated without any GSK3beta and PKA contribution during the progesterone or insulin-induced maturation process. Our results demonstrate that a non-modified physiological process in a cell model can generate the most specific Alzheimer epitope of Tau pathology.
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Affiliation(s)
- P Delobel
- INSERM U422, IMPRT, Institut de Médecine Prédictive et Recherche Thérapeutique, Place de Verdun, 59045, Lille, France
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Morley SJ, Pain VM. Hormone-induced meiotic maturation in Xenopus oocytes occurs independently of p70s6k activation and is associated with enhanced initiation factor (eIF)-4F phosphorylation and complex formation. J Cell Sci 1995; 108 ( Pt 4):1751-60. [PMID: 7615690 DOI: 10.1242/jcs.108.4.1751] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hormone-induced meiotic maturation of the Xenopus oocyte is regulated by complex changes in protein phosphorylation. It is accompanied by a stimulation in the rate of translation, manifest at the level of polypeptide chain initiation. At laser times in the maturation process, this reflects an increased ability for mRNA to interact with the 40 S ribosomal subunit. In mammalian cells there is growing evidence for the regulation of translation by phosphorylation of ribosomal protein S6 and of initiation factors responsible for the binding of mRNA to ribosomes. In this report, we show that although the 70 kDa form of S6 kinase is activated within 1.5 hours in response to progesterone or insulin, a time critical for protein synthesis, its activation is not required for hormone-induced stimulation of translation rates or maturation. In response to progesterone, activation of translation occurs in parallel with enhanced phosphate labelling of eIF-4 alpha and eIF-4 gamma and eIF-4F complex formation, events which are thought to facilitate the interaction of eIF-4F with the mRNA cap structure. However, with insulin, activation of translation occurs prior to detectable de novo phosphorylation of eIF-4F, although a small enhancement of turnover of phosphate on eIF-4 alpha may occur at this early time. With either hormone, enhanced phosphate labelling of eIF-4 alpha is shown to reflect activation of eIF-4 alpha kinase(s), which coincides temporally with activation of p42 MAP and p90rsk kinases. The possible role of initiation factor modification on increased translation rates during meiotic maturation is discussed.
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Affiliation(s)
- S J Morley
- School of Biological Sciences, University of Sussex, Brighton, UK
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5
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Purification and characterization of a novel ribosomal S6 kinase from skeletal muscle of insulin-treated rats. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)37359-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Insulin-stimulated oocyte maturation requires insulin receptor substrate 1 and interaction with the SH2 domains of phosphatidylinositol 3-kinase. Mol Cell Biol 1993. [PMID: 8413261 DOI: 10.1128/mcb.13.11.6653] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Xenopus oocytes from unprimed frogs possess insulin-like growth factor I (IGF-I) receptors but lack insulin and IGF-I receptor substrate 1 (IRS-1), the endogenous substrate of this kinase, and fail to show downstream responses to hormonal stimulation. Microinjection of recombinant IRS-1 protein enhances insulin-stimulated phosphatidylinositol (PtdIns) 3-kinase activity and restores the germinal vesicle breakdown response. Activation of PtdIns 3-kinase results from formation of a complex between phosphorylated IRS-1 and the p85 subunit of PtdIns 3-kinase. Microinjection of a phosphonopeptide containing a pYMXM motif with high affinity for the src homology 2 (SH2) domain of PtdIns 3-kinase p85 inhibits IRS-1 association with and activation of the PtdIns 3-kinase. Formation of the IRS-1-PtdIns 3-kinase complex and insulin-stimulated PtdIns 3-kinase activation are also inhibited by microinjection of a glutathione S-transferase fusion protein containing the SH2 domain of p85. This effect occurs in a concentration-dependent fashion and results in a parallel loss of hormone-stimulated oocyte maturation. These inhibitory effects are specific and are not mimicked by glutathione S-transferase fusion proteins expressing the SH2 domains of ras-GAP or phospholipase C gamma. Moreover, injection of the SH2 domains of p85, ras-GAP, and phospholipase C gamma do not interfere with progesterone-induced oocyte maturation. These data demonstrate that phosphorylation of IRS-1 plays an essential role in IGF-I and insulin signaling in oocyte maturation and that this effect occurs through interactions of the phosphorylated YMXM/YXXM motifs of IRS-1 with SH2 domains of PtdIns 3-kinase or some related molecules.
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7
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Chuang LM, Myers MG, Backer JM, Shoelson SE, White MF, Birnbaum MJ, Kahn CR. Insulin-stimulated oocyte maturation requires insulin receptor substrate 1 and interaction with the SH2 domains of phosphatidylinositol 3-kinase. Mol Cell Biol 1993; 13:6653-60. [PMID: 8413261 PMCID: PMC364728 DOI: 10.1128/mcb.13.11.6653-6660.1993] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Xenopus oocytes from unprimed frogs possess insulin-like growth factor I (IGF-I) receptors but lack insulin and IGF-I receptor substrate 1 (IRS-1), the endogenous substrate of this kinase, and fail to show downstream responses to hormonal stimulation. Microinjection of recombinant IRS-1 protein enhances insulin-stimulated phosphatidylinositol (PtdIns) 3-kinase activity and restores the germinal vesicle breakdown response. Activation of PtdIns 3-kinase results from formation of a complex between phosphorylated IRS-1 and the p85 subunit of PtdIns 3-kinase. Microinjection of a phosphonopeptide containing a pYMXM motif with high affinity for the src homology 2 (SH2) domain of PtdIns 3-kinase p85 inhibits IRS-1 association with and activation of the PtdIns 3-kinase. Formation of the IRS-1-PtdIns 3-kinase complex and insulin-stimulated PtdIns 3-kinase activation are also inhibited by microinjection of a glutathione S-transferase fusion protein containing the SH2 domain of p85. This effect occurs in a concentration-dependent fashion and results in a parallel loss of hormone-stimulated oocyte maturation. These inhibitory effects are specific and are not mimicked by glutathione S-transferase fusion proteins expressing the SH2 domains of ras-GAP or phospholipase C gamma. Moreover, injection of the SH2 domains of p85, ras-GAP, and phospholipase C gamma do not interfere with progesterone-induced oocyte maturation. These data demonstrate that phosphorylation of IRS-1 plays an essential role in IGF-I and insulin signaling in oocyte maturation and that this effect occurs through interactions of the phosphorylated YMXM/YXXM motifs of IRS-1 with SH2 domains of PtdIns 3-kinase or some related molecules.
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Affiliation(s)
- L M Chuang
- Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts
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Pomerance M, Schweighoffer F, Tocque B, Pierre M. Stimulation of mitogen-activated protein kinase by oncogenic Ras p21 in Xenopus oocytes. Requirement for Ras p21-GTPase-activating protein interaction. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)41980-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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9
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Purification and characterization of a cytosolic insulin-stimulated serine kinase from rat liver. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)50156-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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10
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Affiliation(s)
- C G Proud
- Department of Biochemistry, School of Medical Sciences, University of Bristol, England
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11
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Stith BJ, Kirkwood AJ, Wohnlich E. Insulin-like growth factor 1, insulin, and progesterone induce early and late increases in Xenopus oocyte sn-1,2-diacylglycerol levels before meiotic cell division. J Cell Physiol 1991; 149:252-9. [PMID: 1748718 DOI: 10.1002/jcp.1041490211] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
After a 3 to 6 hour incubation, addition of progesterone (the most effective), insulin-like growth factor 1 (IGF-1; the second most effective), or insulin induces meiotic cell division in Xenopus oocytes. Measurement of an endogenous activator of protein kinase C, sn-1,2-diacylglycerol (DAG), by an enzymatic method recording mass demonstrates that all three hormones alter DAG levels. Five seconds after addition, only progesterone transiently reduces DAG levels by about 25%. At 15 minutes after addition, all three hormones produce a peak of DAG (115% to 160% of control values), with the more effective hormones producing a larger increase in DAG. Insulin produces the smallest DAG increase, but the DAG release is longer lasting. Finally, all three hormones induce a second peak in DAG levels just before white spot appearance (at 0.85 GVBD50, where 1.0 GVBD50 is when 50% of the cells have divided). With these data and since an activator of protein kinase C, a phorbol ester, has been found to induce meiosis, the kinase may play a role in early proliferative events at the plasma membrane and in late events at the nucleus.
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Affiliation(s)
- B J Stith
- Department of Biology, University of Colorado, Denver 80217-3364
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12
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Role of protein phosphorylation in the maturation-induced activation of a myelin basic protein kinase from sea star oocytes. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(20)89555-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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13
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Pelech SL, Sanghera JS, Paddon HB, Quayle KA, Brownsey RW. Identification of a major maturation-activated acetyl-CoA carboxylase kinase in sea star oocytes as p44mpk. Biochem J 1991; 274 ( Pt 3):759-67. [PMID: 1672814 PMCID: PMC1149976 DOI: 10.1042/bj2740759] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Maturation-activated protein-serine/threonine kinases were investigated in the high-speed supernatant fractions from sea-star oocytes harvested at the time of germinal vesicle breakdown. One of the major stimulated protein kinases able to phosphorylate acetyl-CoA carboxylase in these extracts was found to co-purify with a 44 kDa myelin basic protein kinase (p44mpk) that is activated with a similar time course during oocyte maturation. Purified sea-star oocyte p44mpk phosphorylated acetyl-CoA carboxylase (purified from rat liver) predominantly on serine and to a small extent on threonine. Furthermore, the phosphorylation of acetyl-CoA carboxylase occurred principally on a tryptic phosphopeptide which displayed electrophoretic and chromatographic properties very similar to those of the peptide that has previously been shown to undergo increased phosphorylation in response to insulin in rat adipocytes [Brownsey & Denton (1982) Biochem. J. 202, 77-86]. The acetyl-CoA carboxylase was phosphorylated at a similar rate and to a similar extent by casein kinase II, which was also purified from maturing sea-star oocytes. Although casein kinase II was also activated approximately 3-fold near the time of nuclear envelope breakdown, it was responsible for only a minor component of the total enhanced acetyl-CoA carboxylase kinase activity measured in the soluble extracts from maturing oocytes. Acetyl-CoA carboxylase was a relatively poor substrate for the major S6 peptide kinase activity that was also stimulated during resumption of meiosis in the oocytes. The properties of the p44mpk are reminiscent of those of a microtubule-associated protein 2 (MAP-2) kinase that is activated in response to insulin and other mitogens in mammalian cells [Ray & Sturgill (1988) Proc. Natl. Acad. Sci. U.S.A. 85, 3753-3757; Hoshi, Nishida & Sakai (1988) J. Biol. Chem. 263, 5396-5401]. It is intriguing that several of the mammalian protein kinases that are acutely activated after mitogenic prompting of quiescent mouse fibroblasts (i.e. G0 to G1 transition), such as MAP-2 kinase, casein kinase II and S6 kinase II, have counterparts that are activated during M-phase in maturing sea star oocytes.
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Affiliation(s)
- S L Pelech
- Biomedical Research Centre, University of British Columbia, Vancouver, Canada
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Abstract
The molecular events responsible for controlling cell growth and development, as well as their coordinate interaction is only beginning to be revealed. At the basis of these controlling events are hormones, growth factors and mitogens which, through transmembrane signalling trigger an array of cellular responses, initiated by receptor-associated tyrosine kinases, which in turn either directly or indirectly mediate their effects through serine/threonine protein kinases. Utilizing the obligatory response of activation of protein synthesis in cell growth and development, we describe efforts to work backwards along the regulatory pathway to the receptor, identifying those molecular components involved in modulating the rate of translation. We begin by describing the components and steps of protein synthesis and then discuss in detail the regulatory pathways involved in the mitogenic response of eukaryotic cells and during meiotic maturation of oocytes. Finally we discuss possible future work which will further our understanding of these systems.
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Affiliation(s)
- S J Morley
- Friedrich Miescher-Institut, Basel, Switzerland
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Opresko LK, Wiley HS. Functional reconstitutional of the human epidermal growth factor receptor system in Xenopus oocytes. J Biophys Biochem Cytol 1990; 111:1661-71. [PMID: 1976639 PMCID: PMC2116234 DOI: 10.1083/jcb.111.4.1661] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
We have expressed the human EGF receptor (hEGF-R) in Xenopus oocytes by injecting mRNA synthesized in vitro using SP6 vectors containing receptor cDNAs. Each oocyte could express over 1 x 10(10) receptors of a single affinity class and these were able to bind and rapidly internalize EGF. Occupancy resulted in receptor tyrosine autophosphorylation, downregulation, and release of intracellular calcium. Occupied receptors also rapidly induced meiotic maturation in stage VI oocytes. Receptors lacking tyrosine kinase activity bound EGF normally, but did not downregulate or induce any biological responses. The rate of oocyte maturation was proportional to hEGF-R occupancy and was significantly faster than progesterone-induced maturation at nanomolar EGF concentrations. Mutant hEGF-R truncated at residue 973 displayed identical phenotypes in both mammalian cells and oocytes in that they were defective in their ability to release intracellular calcium, undergo ligand induced internalization and receptor downregulation. However, these receptors were fully capable of inducing oocyte maturation. The remarkable retention of specific biological activities of different hEGF-R in the context of oocytes suggests that this receptor system interacts with generally available cellular components that have been conserved during evolution. In addition, it suggests that cell surface tyrosine kinase activity may play an important role in regulating resumption of the cell cycle.
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Affiliation(s)
- L K Opresko
- Department of Pathology, University of Utah Medical Center, Salt Lake City 84132
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Haccard O, Jessus C, Cayla X, Goris J, Merlevede W, Ozon R. In vivo activation of a microtubule-associated protein kinase during meiotic maturation of the Xenopus oocyte. EUROPEAN JOURNAL OF BIOCHEMISTRY 1990; 192:633-42. [PMID: 2170126 DOI: 10.1111/j.1432-1033.1990.tb19270.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We have characterized a serine/threonine protein kinase from Xenopus metaphase-II-blocked oocytes, which phosphorylates in vitro the microtubule-associated protein 2 (MAP2). The MAP2 kinase activity, undetectable in prophase oocytes, is activated during the progesterone-induced meiotic maturation (G2-M transition of the cell cycle). p-Nitrophenyl phosphate, a phosphatase inhibitor, is required to prevent spontaneous deactivation of the MAP2 kinase in crude preparations; conversely, the partially purified enzyme can be in vitro deactivated by the low-Mr polycation-stimulated (PCSL) phosphatase (also termed protein phosphatase 2A2), working as a phosphoserine/phosphothreonine-specific phosphatase and not as a phosphotyrosyl phosphatase indicating that phosphorylation of serine/threonine is necessary for its activity. S6 kinase, a protein kinase activated during oocyte maturation which phosphorylates in vitro ribosomal protein S6 and lamin C, can be deactivated in vitro by PCSL phosphatase. S6 kinase from prophase oocytes can also be activated in vitro in fractions known to contain all the factors necessary to convert pre-M-phase-promoting factor (pre-MPF) to MPF. Active MAP2 kinase can activate in vitro the inactive S6 kinase present in prophase oocytes or reactivate S6 kinase previously inactivated in vitro by PCSL phosphatase. These data are consistent with the hypothesis that the MAP2 kinase is a link of the meiosis signalling pathway and is activated by a serine/threonine kinase. This will lead to the regulation of further steps in the cell cycle, such as microtubular reorganisation and S6 kinase activation.
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Affiliation(s)
- O Haccard
- Institut National de la Recherche Agronomique/Unité Associeé du Centre National de la Recherche Scientifique 555, Université P. et M. Curie, Paris, France
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Cicirelli MF, Tonks NK, Diltz CD, Weiel JE, Fischer EH, Krebs EG. Microinjection of a protein-tyrosine-phosphatase inhibits insulin action in Xenopus oocytes. Proc Natl Acad Sci U S A 1990; 87:5514-8. [PMID: 2164686 PMCID: PMC54355 DOI: 10.1073/pnas.87.14.5514] [Citation(s) in RCA: 120] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
A protein-tyrosine-phosphatase (PTPase 1B; protein-tyrosine-phosphate phosphohydrolase, EC 3.1.3.48), specific for phosphotyrosyl residues, was microinjected into Xenopus oocytes. This resulted in a 3- to 5-fold increase in PTPase activity over endogenous levels. The PTPase blocked the insulin-stimulated phosphorylation of tyrosyl residues on endogenous proteins, including a protein having a molecular mass in the same range as the beta subunit of the insulin or insulin-like growth factor I receptor. PTPase 1B also blocked the activation of an S6 peptide kinase--i.e., an enzyme recognizing a peptide having the sequence RRLSSLRA found in a segment of ribosomal protein S6 and known to be activated early in response to insulin. On the other hand, the insulin stimulation of an S6 kinase, detected by using 40S ribosomes as substrate, was unaffected even though PTPase 1B partially prevented the phosphorylation of ribosomal protein S6 in vivo. Mono Q chromatography of insulin-treated oocyte extracts revealed two main peaks of S6 kinase activity. Fractions from the first peak displayed S6 peptide kinase activity that was essentially abolished in profiles from PTPase 1B-injected oocytes. Material from the second peak, which was best revealed by using 40S ribosomes as substrate and had comparatively little S6 peptide kinase activity, was minimally affected by PTPase 1B. These observations suggest that at least two distinct "S6 kinases" are involved in ribosomal protein S6 phosphorylation in vivo and that the activation pathways for these enzymes differ in their sensitivity to PTPase 1B.
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Affiliation(s)
- M F Cicirelli
- Howard Hughes Medical Institute, University of Washington School of Medicine, Seattle 98195
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18
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Meier KE, Weiel JE, Bloom TJ, Krebs EG. Regulation of S6 kinase activity in Madin-Darby canine kidney renal epithelial cells. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39610-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Effect of microinjection of a low-Mr human placenta protein tyrosine phosphatase on induction of meiotic cell division in Xenopus oocytes. Mol Cell Biol 1990. [PMID: 2153916 DOI: 10.1128/mcb.10.2.458] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Homogeneous preparations of a protein phosphatase that is specific for phosphotyrosyl residues (protein tyrosine phosphatase [PTPase] 1B) were isolated from human placenta and microinjected into Xenopus oocytes. This resulted in an increase in activity of up to 10-fold over control levels, as measured in homogenates with use of an artificial substrate (reduced carboxamidomethylated and maleylated lysozyme). Microinjected PTPase was stable for at least 18 h. It is distributed within the oocyte in a manner similar to the endogenous activity and is suggestive of an interaction with cellular structures or molecules located predominantly in the animal hemisphere. The phosphatase markedly retarded (by up to 5 h) maturation induced by insulin. This, in conjunction with the demonstration that PTPase 1B abolished insulin stimulation of an S6 peptide (RRLSSLRA) kinase concomitant with a decrease in the phosphorylation of tyrosyl residues in a protein with the same apparent Mr as the beta subunit of the insulin and insulinlike growth factor 1 receptors (M. F. Cicirelli, N. K. Tonks, C. D. Diltz, E. H. Fischer, and E. G. Krebs, submitted for publication), provides further support for an essential role of protein tyrosine phosphorylation in insulin action. Furthermore, maturation was significantly retarded even when the PTPase was injected 2 to 4 h after exposure of the cells to insulin. PTPase 1B also retarded maturation induced by progesterone and maturation-promoting factor, which presumably do not act through the insulin receptor. These data point to a second site of action of the PTPase in the pathway of meiotic cell division, downstream of the insulin receptor and following the appearance of active maturation-promoting factor.
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Tonks NK, Cicirelli MF, Diltz CD, Krebs EG, Fischer EH. Effect of microinjection of a low-Mr human placenta protein tyrosine phosphatase on induction of meiotic cell division in Xenopus oocytes. Mol Cell Biol 1990; 10:458-63. [PMID: 2153916 PMCID: PMC360813 DOI: 10.1128/mcb.10.2.458-463.1990] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Homogeneous preparations of a protein phosphatase that is specific for phosphotyrosyl residues (protein tyrosine phosphatase [PTPase] 1B) were isolated from human placenta and microinjected into Xenopus oocytes. This resulted in an increase in activity of up to 10-fold over control levels, as measured in homogenates with use of an artificial substrate (reduced carboxamidomethylated and maleylated lysozyme). Microinjected PTPase was stable for at least 18 h. It is distributed within the oocyte in a manner similar to the endogenous activity and is suggestive of an interaction with cellular structures or molecules located predominantly in the animal hemisphere. The phosphatase markedly retarded (by up to 5 h) maturation induced by insulin. This, in conjunction with the demonstration that PTPase 1B abolished insulin stimulation of an S6 peptide (RRLSSLRA) kinase concomitant with a decrease in the phosphorylation of tyrosyl residues in a protein with the same apparent Mr as the beta subunit of the insulin and insulinlike growth factor 1 receptors (M. F. Cicirelli, N. K. Tonks, C. D. Diltz, E. H. Fischer, and E. G. Krebs, submitted for publication), provides further support for an essential role of protein tyrosine phosphorylation in insulin action. Furthermore, maturation was significantly retarded even when the PTPase was injected 2 to 4 h after exposure of the cells to insulin. PTPase 1B also retarded maturation induced by progesterone and maturation-promoting factor, which presumably do not act through the insulin receptor. These data point to a second site of action of the PTPase in the pathway of meiotic cell division, downstream of the insulin receptor and following the appearance of active maturation-promoting factor.
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Affiliation(s)
- N K Tonks
- Department of Biochemistry, University of Washington, Seattle 98195
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Purification and characterization of a maturation-activated myelin basic protein kinase from sea star oocytes. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)40193-2] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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