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Redpath G, Deo N. Serotonin: an overlooked regulator of endocytosis and endosomal sorting? Biol Open 2022; 11:bio059057. [PMID: 35076063 PMCID: PMC8801889 DOI: 10.1242/bio.059057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 12/09/2021] [Indexed: 12/23/2022] Open
Abstract
Serotonin is a neurotransmitter and a hormone that is typically associated with regulating our mood. However, the serotonin transporter and receptors are expressed throughout the body, highlighting the much broader, systemic role of serotonin in regulating human physiology. A substantial body of data strongly implicates serotonin as a fundamental regulator of endocytosis and endocytic sorting. Serotonin has the potential to enhance endocytosis through three distinct mechanisms - serotonin signalling, serotonylation and insertion into the plasma membrane - although the interplay and relationship between these mechanisms has not yet been explored. Endocytosis is central to the cellular response to the extracellular environment, controlling receptor distribution on the plasma membrane to modulate signalling, neurotransmitter release and uptake, circulating protein and lipid cargo uptake, and amino acid internalisation for cell proliferation. Uncovering the range of cellular and physiological circumstances in which serotonin regulates endocytosis is of great interest for our understanding of how serotonin regulates mood, and also the fundamental understanding of endocytosis and its regulation throughout the body. This article has an associated Future Leader to Watch interview with the first author of the paper.
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Affiliation(s)
- Gregory Redpath
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences and the ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney 2052, Australia
| | - Nikita Deo
- Department of Biochemistry, University of Otago, Dunedin 9016, New Zealand
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2
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Heckman CA, Biswas T, Dimick DM, Cayer ML. Activated Protein Kinase C (PKC) Is Persistently Trafficked with Epidermal Growth Factor (EGF) Receptor. Biomolecules 2020; 10:E1288. [PMID: 32906765 PMCID: PMC7563713 DOI: 10.3390/biom10091288] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/02/2020] [Accepted: 09/05/2020] [Indexed: 12/22/2022] Open
Abstract
Protein kinase Cs (PKCs) are activated by lipids in the plasma membrane and bind to a scaffold assembled on the epidermal growth factor (EGF) receptor (EGFR). Understanding how this complex is routed is important, because this determines whether EGFR is degraded, terminating signaling. Here, cells were preincubated in EGF-tagged gold nanoparticles, then allowed to internalize them in the presence or absence of a phorbol ester PKC activator. PKC colocalized with EGF-tagged nanoparticles within 5 min and migrated with EGFR-bearing vesicles into the cell. Two conformations of PKC-epsilon were distinguished by different primary antibodies. One, thought to be enzymatically active, was on endosomes and displayed a binding site for antibody RR (R&D). The other, recognized by Genetex green (GG), was soluble, on actin-rich structures, and loosely bound to vesicles. During a 15-min chase, EGF-tagged nanoparticles entered large, perinuclear structures. In phorbol ester-treated cells, vesicles bearing EGF-tagged nanoparticles tended to enter this endocytic recycling compartment (ERC) without the GG form. The correlation coefficient between the GG (inactive) and RR conformations on vesicles was also lower. Thus, active PKC has a Charon-like function, ferrying vesicles to the ERC, and inactivation counteracts this function. The advantage conferred on cells by aggregating vesicles in the ERC is unclear.
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Affiliation(s)
- Carol A. Heckman
- Department of Biological Sciences, 217 Life Science Building, Bowling Green State University, Bowling Green, OH 43403, USA;
| | - Tania Biswas
- Department of Biological Sciences, 217 Life Science Building, Bowling Green State University, Bowling Green, OH 43403, USA;
| | - Douglas M. Dimick
- Department of Physics & Astronomy, 104 Overman Hall, Bowling Green State University, Bowling Green, OH 43403, USA;
| | - Marilyn L. Cayer
- Center for Microscopy & Microanalysis, 217 Life Science Building, Bowling Green State University, Bowling Green, OH 43403, USA;
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Wegener JW, Loga F, Stegner D, Nieswandt B, Hofmann F. Phospholipase D1 is involved in α‐adrenergic contraction of murine vascular smooth muscle. FASEB J 2014; 28:1044-8. [DOI: 10.1096/fj.13-237925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jörg W. Wegener
- For 923, Institut für Pharmakologie and Toxikologie, Technische Universität MünchenMünchenGermany
| | - Florian Loga
- For 923, Institut für Pharmakologie and Toxikologie, Technische Universität MünchenMünchenGermany
| | - David Stegner
- Lehrstuhl für Experimentelle BiomedizinUniversitätsklinikum Würzburg and Rudolf‐Virchow‐ZentrumDeutsche Forschungsgemeinschaft (DFG) Forschungszentrum für Experimentelle BiomedizinUniversität WürzburgWürzburgGermany
| | - Bernhard Nieswandt
- Lehrstuhl für Experimentelle BiomedizinUniversitätsklinikum Würzburg and Rudolf‐Virchow‐ZentrumDeutsche Forschungsgemeinschaft (DFG) Forschungszentrum für Experimentelle BiomedizinUniversität WürzburgWürzburgGermany
| | - Franz Hofmann
- For 923, Institut für Pharmakologie and Toxikologie, Technische Universität MünchenMünchenGermany
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Liu M, Idkowiak-Baldys J, Roddy PL, Baldys A, Raymond J, Clarke CJ, Hannun YA. Sustained activation of protein kinase C induces delayed phosphorylation and regulates the fate of epidermal growth factor receptor. PLoS One 2013; 8:e80721. [PMID: 24244711 PMCID: PMC3823608 DOI: 10.1371/journal.pone.0080721] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 10/04/2013] [Indexed: 01/11/2023] Open
Abstract
It is well established that acute activation of members of the protein kinase C (PKC) family induced by activation of cellular receptors can transduce extracellular stimuli to intracellular signaling. However, the functions of sustained activation of PKC are not well studied. We have previously shown that sustained activation of classical PKC isoforms over 15-60 min induced the formation of the pericentrion, a subset of recycling endosomes that are sequestered perinuclearly in a PKC- and phospholipase D (PLD)-dependent manner. In this study, we investigated the role of this process in the phosphorylation of EGFR on threonine 654 (Thr-654) and in the regulation of intracellular trafficking and fate of epidermal growth factor receptor (EGFR). Sustained stimulation of the angiotensin II receptor induced translocation of the EGFR to the pericentrion, which in turn prevents full access of EGF to the EGFR. These effects required PKC and PLD activities, and direct stimulation of PKC with phorbol esters was sufficient to reproduce these effects. Furthermore, activation of PKC induced delayed phosphorylation of EGFR on Thr-654 that coincided with the formation of the pericentrion and which was dependent on PLD and endocytosis of EGFR. Thus, Thr-654 phosphorylation required the formation of the pericentrion. On the other hand, using a T654A mutant of EGFR, we find that the phosphorylation on Thr-654 was not required for translocation of EGFR to the pericentrion but was required for protection of EGFR from degradation in response to EGF. Taken together, these results demonstrate a novel role for the pericentrion in the regulation of EGFR phosphorylation, which in turn is important for the fates of EGFR.
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Affiliation(s)
- Mengling Liu
- Department of Medicine and The Stony Brook Cancer Center, Stony Brook University, Stony Brook, New York, United States of America
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Jolanta Idkowiak-Baldys
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Patrick L. Roddy
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Aleksander Baldys
- Division of Nephrology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, United States of America
- Medical and Research Services, Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina, United States of America
| | - John Raymond
- Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Christopher J. Clarke
- Department of Medicine and The Stony Brook Cancer Center, Stony Brook University, Stony Brook, New York, United States of America
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Yusuf A. Hannun
- Department of Medicine and The Stony Brook Cancer Center, Stony Brook University, Stony Brook, New York, United States of America
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, United States of America
- * E-mail:
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Zeng L, Webster SV, Newton PM. The biology of protein kinase C. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 740:639-61. [PMID: 22453963 DOI: 10.1007/978-94-007-2888-2_28] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This review gives a basic introduction to the biology of protein kinase C, one of the first calcium-dependent kinases to be discovered. We review the structure and function of protein kinase C, along with some of the substrates of individual isoforms. We then review strategies for inhibiting PKC in experimental systems and finally discuss the therapeutic potential of targeting PKC. Each aspect is covered in summary, with links to detailed resources where appropriate.
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Affiliation(s)
- Lily Zeng
- School of Medicine, University of California, San Francisco, CA, USA
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El-Shewy HM, Abdel-Samie SA, Al Qalam AM, Lee MH, Kitatani K, Anelli V, Jaffa AA, Obeid LM, Luttrell LM. Phospholipase C and protein kinase C-β 2 mediate insulin-like growth factor II-dependent sphingosine kinase 1 activation. Mol Endocrinol 2011; 25:2144-56. [PMID: 22016563 DOI: 10.1210/me.2011-0101] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
We recently reported that IGF-II binding to the IGF-II/mannose-6-phosphate (M6P) receptor activates the ERK1/2 cascade by triggering sphingosine kinase 1 (SK1)-dependent transactivation of G protein-coupled sphingosine 1-phosphate (S1P) receptors. Here, we investigated the mechanism of IGF-II/M6P receptor-dependent sphingosine kinase 1 (SK1) activation in human embryonic kidney 293 cells. Pretreating cells with protein kinase C (PKC) inhibitor, bisindolylmaleimide-I, abolished IGF-II-stimulated translocation of green fluorescent protein (GFP)-tagged SK1 to the plasma membrane and activation of endogenous SK1, implicating PKC as an upstream regulator of SK1. Using confocal microscopy to examine membrane translocation of GFP-tagged PKCα, β1, β2, δ, and ζ, we found that IGF-II induced rapid, transient, and isoform-specific translocation of GFP-PKCβ2 to the plasma membrane. Immunoblotting of endogenous PKC phosphorylation confirmed PKCβ2 activation in response to IGF-II. Similarly, IGF-II stimulation caused persistent membrane translocation of the kinase-deficient GFP-PKCβ2 (K371R) mutant, which does not dissociate from the membrane after translocation. IGF-II stimulation increased diacylglycerol (DAG) levels, the established activator of classical PKC. Interestingly, the polyunsaturated fraction of DAG was increased, indicating involvement of phosphatidyl inositol/phospholipase C (PLC). Pretreating cells with the PLC inhibitor, U73122, attenuated IGF-II-dependent DAG production and PKCβ2 phosphorylation, blocked membrane translocation of the kinase-deficient GFP-PKCβ2 (K371R) mutant, and reduced sphingosine 1-phosphate production, suggesting that PLC/PKCβ2 are upstream regulators of SK1 in the pathway. Taken together, these data provide evidence that activation of PLC and PKCβ2 by the IGF-II/M6P receptor are required for the activation of SK1.
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Affiliation(s)
- Hesham M El-Shewy
- Departments of Medicine, Medical University of South Carolina, Charleston, South Carolina 29425, USA.
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8
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Chen X, Zhang X, Jia C, Xu J, Gao H, Zhang G, Du X, Zhang H. Membrane depolarization increases membrane PtdIns(4,5)P2 levels through mechanisms involving PKC βII and PI4 kinase. J Biol Chem 2011; 286:39760-7. [PMID: 21953466 DOI: 10.1074/jbc.m111.289090] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
In a previous study, we showed that membrane depolarization induced elevation of membrane phosphatidylinositol 4,5-bisphosphates (PtdIns(4,5)P(2), also known as PIP(2)) and subsequently increased the KCNQ2/Q3 currents expressed in Xenopus oocytes through increased PI4 kinase activity. In this study, the underlying mechanism for this depolarization-induced enhancement of PIP(2) synthesis was further investigated. Our results indicate that activation of protein kinase C (PKC) isozyme βII was responsible for the enhanced PIP(2) synthesis. We found that phorbol-12-myristate, 13-acetate (PMA), an activator of PKC, mimicked the effects of the membrane depolarization by increasing KCNQ2/Q3 activity, elevating membrane PIP(2) levels and increasing activity of PI4 kinase β. Furthermore, membrane depolarization enhanced PKC activity. The effects of both depolarization and PMA were blocked by a PKC inhibitor or PI4 kinase β RNA interference. Further results demonstrate that the depolarization selectively activated the PKC βII isoform and enhanced its interaction with PI4 kinase β. These results reveal that the depolarization-induced elevation of membrane PIP(2) is through activation of PKC and the subsequent increased activity of PI4 kinase β.
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Affiliation(s)
- Xingjuan Chen
- Key Laboratory of Neural and Vascular Biology, Ministry of Education, Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei, 050017, China
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El-Osta MA, Idkowiak-Baldys J, Hannun YA. Delayed phosphorylation of classical protein kinase C (PKC) substrates requires PKC internalization and formation of the pericentrion in a phospholipase D (PLD)-dependent manner. J Biol Chem 2011; 286:19340-53. [PMID: 21478146 DOI: 10.1074/jbc.m110.152330] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
It was previously demonstrated that sustained activation (30-60 min) of protein kinase C (PKC) results in translocation of PKC α and βII to the pericentrion, a dynamic subset of the recycling compartment whose formation is dependent on PKC and phospholipase D (PLD). Here we investigated whether the formation of the pericentrion modulates the ability of PKC to phosphorylate substrates, especially if it reduces substrate phosphorylation by sequestering PKC. Surprisingly, using an antibody that detects phosphosubstrates of classical PKCs, the results showed that the majority of PKC phosphosubstrates are phosphorylated with delayed kinetics, correlating with the time frame of PKC translocation to the pericentrion. Substrate phosphorylation was blocked by PLD inhibitors and was not observed in response to activation of a PKC βII mutant (F663D) that is defective in interaction with PLD and in internalization. Phosphorylation was also inhibited by blocking clathrin-dependent endocytosis, demonstrating a requirement for endocytosis for the PKC-dependent major phosphorylation effects. Serotonin receptor activation by serotonin showed a similar response to phorbol 12-myristate 13-acetate, implicating a potential role of delayed kinetics in G protein-coupled receptor signaling. Evaluation of candidate substrates revealed that the phosphorylation of the PKC substrate p70S6K kinase behaved in a similar manner. Gradient-based fractionation revealed that the majority of these PKC substrates reside within the pericentrion-enriched fractions and not in the plasma membrane. Finally, proteomic analysis of the pericentrion-enriched fractions revealed several proteins as known PKC substrates and/or proteins involved in endocytic trafficking. These results reveal an important role for PKC internalization and for the pericentrion as key determinants/amplifiers of PKC action.
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Affiliation(s)
- Mohamad A El-Osta
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
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10
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Milhas D, Clarke CJ, Idkowiak-Baldys J, Canals D, Hannun YA. Anterograde and retrograde transport of neutral sphingomyelinase-2 between the Golgi and the plasma membrane. Biochim Biophys Acta Mol Cell Biol Lipids 2010; 1801:1361-74. [PMID: 20713176 DOI: 10.1016/j.bbalip.2010.08.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Revised: 07/30/2010] [Accepted: 08/02/2010] [Indexed: 02/06/2023]
Abstract
The activation of neutral sphingomyelinase-2 (nSMase2) and consequent ceramide production are implicated in many stress-induced signaling pathways. Trafficking of nSMase2 from the Golgi compartment to the plasma membrane (PM) in response to signaling stimuli has been described. However, the precise mechanisms of transport remain unknown. This study aimed to investigate the trafficking of nSMase2 between the Golgi and the PM. We show here that V5-nSMase2 localizes at the PM and Golgi in MCF-7 cells and confirm relocalization of nSMase2 to the PM at confluence. Although cycloheximide (CHX) treatment partially inhibited the Golgi localization of GFP-nSMase2, recovery of GFP-nSMase2 to an intracellular compartment was still observed after photobleaching. Moreover, in the presence of CHX, GFP- and V5-nSMase2 co-localized with endosomal/recycling markers. In HEK293 cells, activation of either protein kinase C-alpha or betaII, with the phorbol ester PMA led to relocalization of both wild-type and inactive nSMase2 to the pericentrion, a PKC-dependent subset of recycling endosomes. Finally, inhibition of nSMase2 endocytosis by K+depletion reduced the intracellular pool of nSMase2 and increased nSMase2 activity resulting in elevated ceramide levels. Altogether, these results suggest that nSMase2 traffics from the Golgi to the PM as a membrane protein en route to the cell surface and recycles back to the Golgi through the endosomal/recycling compartment. Moreover, the recycling of nSMase2 from the PM is important for its catalytic regulation.
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Affiliation(s)
- Delphine Milhas
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA
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11
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Ai E, Skop AR. Endosomal recycling regulation during cytokinesis. Commun Integr Biol 2010; 2:444-7. [PMID: 19907714 DOI: 10.4161/cib.2.5.8931] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Accepted: 04/05/2009] [Indexed: 11/19/2022] Open
Abstract
Successful cytokinesis is critical for cell proliferation and development. In animal cells, cytokinesis relies on temporally and spatially regulated membrane addition to the cleavage site. An important source for the new membrane is recycling endosomes. Yet how these endocytic vesicles are transported and regulated remains unclear. Several potential factors have been recently identified that regulate the trafficking of recycling endosomes during cytokinesis. Dynein and dynactin are required for the retrograde transport of recycling endosomes, while Kinesin-1 is responsible for endosome delivery to the furrow and midbody. Other regulators of recycling endosome trafficking have been identified, including RACK1, JIP3/4 and ECT2, which target recycling endosomes during the cell cycle. Here, we provide insights into the mechanisms controlling endosomal trafficking during cytokinesis.
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Affiliation(s)
- Erkang Ai
- Department of Genetics & Medical Genetics, University of Wisconsin-Madison, Madison, WI 53706, USA
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12
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Joseph EK, Levine JD. Multiple PKCε-dependent mechanisms mediating mechanical hyperalgesia. Pain 2010; 150:17-21. [PMID: 20456866 DOI: 10.1016/j.pain.2010.02.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 01/11/2010] [Accepted: 02/05/2010] [Indexed: 12/14/2022]
Abstract
We have recently implicated mitochondrial mechanisms in models of neuropathic and inflammatory pain, in some of which a role of protein kinase Cepsilon (PKCepsilon) has also been implicated. Since mitochondria contain several proteins that are targets of PKCepsilon, we evaluated the role of mitochondrial mechanisms in mechanical hyperalgesia induced by proinflammatory cytokines that induce PKCepsilon-dependent nociceptor sensitization, and by a direct activator of PKCepsilon (psiepsilonRACK), in the rat. Prostaglandin E(2) (PGE(2))-induced hyperalgesia is short lived in naïve rats, while it is prolonged in psiepsilonRACK pre-treated rats, a phenomenon referred to as priming. Inhibitors of two closely related mitochondrial functions, electron transport (complexes I-V) and oxidative stress (reactive oxygen species), attenuated mechanical hyperalgesia induced by intradermal injection of psiepsilonRACK. In marked contrast, in a PKCepsilon-dependent form of mechanical hyperalgesia induced by prostaglandin E(2) (PGE(2)), inhibitors of mitochondrial function failed to attenuate hyperalgesia. These studies support the suggestion that at least two downstream signaling pathways can mediate the hyperalgesia induced by activating PKCepsilon.
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Affiliation(s)
- Elizabeth K Joseph
- Departments of Medicine and Oral Surgery, and Division of Neuroscience, University of California, San Francisco, USA
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Voris JP, Sitailo LA, Rahn HR, Defnet A, Gerds AT, Sprague R, Yadav V, Caroline Le Poole I, Denning MF. Functional alterations in protein kinase C beta II expression in melanoma. Pigment Cell Melanoma Res 2009; 23:216-24. [PMID: 20015121 DOI: 10.1111/j.1755-148x.2009.00664.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Protein kinase C (PKC) is a heterogeneous family of serine/threonine protein kinases that have different biological effects in normal and neoplastic melanocytes (MCs). To explore the mechanism behind their differential response to PKC activation, we analyzed the expression profile of all nine PKC isoforms in normal human MCs, HPV16 E6/E7 immortalized MCs, and a panel of melanoma cell lines. We found reduced PKCbeta and increased PKCzeta and PKCiota expression at both the protein and mRNA levels in immortalized MCs and melanoma lines. We focused on PKCbeta as it has been functionally linked to melanin production and oxidative stress response. Re-expression of PKCbeta in melanoma cells inhibited colony formation in soft agar, indicating that PKCbeta loss in melanoma is important for melanoma growth. PKCbetaII, but not PKCbetaI, was localized to the mitochondria, and inhibition of PKCbeta significantly reduced UV-induced reactive oxygen species (ROS) in MCs with high PKCbeta expression. Thus alterations in PKCbeta expression in melanoma contribute to their neoplastic phenotype, possibly by reducing oxidative stress, and may constitute a selective therapeutic target.
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Affiliation(s)
- John P Voris
- The Oncology Institute, Loyola University Chicago, Maywood, IL, USA
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14
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Idkowiak-Baldys J, Baldys A, Raymond JR, Hannun YA. Sustained receptor stimulation leads to sequestration of recycling endosomes in a classical protein kinase C- and phospholipase D-dependent manner. J Biol Chem 2009; 284:22322-22331. [PMID: 19525236 PMCID: PMC2755955 DOI: 10.1074/jbc.m109.026765] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Indexed: 11/06/2022] Open
Abstract
Considerable insight has been garnered on initial mechanisms of endocytosis of plasma membrane proteins and their subsequent trafficking through the endosomal compartment. It is also well established that ligand stimulation of many plasma membrane receptors leads to their internalization. However, stimulus-induced regulation of endosomal trafficking has not received much attention. In previous studies, we showed that sustained stimulation of protein kinase C (PKC) with phorbol esters led to sequestration of recycling endosomes in a juxtanuclear region. In this study, we investigated whether G-protein-coupled receptors that activate PKC exerted effects on endosomal trafficking. Stimulation of cells with serotonin (5-hydroxytryptamine (5-HT)) led to sequestration of the 5-HT receptor (5-HT2AR) into a Rab11-positive juxtanuclear compartment. This sequestration coincided with translocation of PKC as shown by confocal microscopy. Mechanistically the observed sequestration of 5-HT2AR was shown to require continuous PKC activity because it was inhibited by pretreatment with classical PKC inhibitor Gö6976 and could be reversed by posttreatment with this inhibitor. In addition, classical PKC autophosphorylation was necessary for receptor sequestration. Moreover inhibition of phospholipase D (PLD) activity and inhibition of PLD1 and PLD2 using dominant negative constructs also prevented this process. Functionally this sequestration did not affect receptor desensitization or resensitization as measured by intracellular calcium increase. However, the PKC- and PLD-dependent sequestration of receptors resulted in co-sequestration of other plasma membrane proteins and receptors as shown for epidermal growth factor receptor and protease activated receptor-1. This led to heterologous desensitization of those receptors and diverted their cellular fate by protecting them from agonist-induced degradation. Taken together, these results demonstrate a novel role for sustained receptor stimulation in regulation of intracellular trafficking, and this process requires sustained stimulation of PKC and PLD.
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Affiliation(s)
| | - Aleksander Baldys
- Division of Nephrology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina 29425 and
- Medical and Research Services, Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina 29401
| | - John R. Raymond
- Division of Nephrology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina 29425 and
- Medical and Research Services, Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina 29401
| | - Yusuf A. Hannun
- From the Department of Biochemistry and Molecular Biology and
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15
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Abstract
Protein kinase C (PKC) isoforms comprise a family of lipid-activated enzymes that have been implicated in a wide range of cellular functions. PKCs are modular enzymes comprised of a regulatory domain (that contains the membrane-targeting motifs that respond to lipid cofactors, and in the case of some PKCs calcium) and a relatively conserved catalytic domain that binds ATP and substrates. These enzymes are coexpressed and respond to similar stimulatory agonists in many cell types. However, there is growing evidence that individual PKC isoforms subserve unique (and in some cases opposing) functions in cells, at least in part as a result of isoform-specific subcellular compartmentalization patterns, protein-protein interactions, and posttranslational modifications that influence catalytic function. This review focuses on the structural basis for differences in lipid cofactor responsiveness for individual PKC isoforms, the regulatory phosphorylations that control the normal maturation, activation, signaling function, and downregulation of these enzymes, and the intra-/intermolecular interactions that control PKC isoform activation and subcellular targeting in cells. A detailed understanding of the unique molecular features that underlie isoform-specific posttranslational modification patterns, protein-protein interactions, and subcellular targeting (i.e., that impart functional specificity) should provide the basis for the design of novel PKC isoform-specific activator or inhibitor compounds that can achieve therapeutically useful changes in PKC signaling in cells.
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Affiliation(s)
- Susan F Steinberg
- Department of Pharmacology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA.
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16
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Poussin MA, Leitges M, Goldfine H. The ability of Listeria monocytogenes PI-PLC to facilitate escape from the macrophage phagosome is dependent on host PKCbeta. Microb Pathog 2008; 46:1-5. [PMID: 18996181 DOI: 10.1016/j.micpath.2008.09.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Revised: 08/27/2008] [Accepted: 09/12/2008] [Indexed: 11/28/2022]
Abstract
Listeria monocytogenes are facultative intracellular pathogenic bacteria that can infect macrophages as well as non-professional phagocytes. After entry in the host cell, the bacteria escape from the phagosome into the cytoplasm. In murine macrophages and in cell lines derived from these cells, escape of L. monocytogenes from the phagosome is absolutely dependent on listeriolysin O (LLO) and facilitated by a secreted phosphatidylinositol-specific phospholipase C (PI-PLC). Work in this laboratory has previously demonstrated a LLO and PI-PLC-dependent translocation of host PKCbeta isoforms. Pharmacological inhibition of PKCbeta resulted in a significant reduction in permeabilization of the phagosome, and in the number of bacteria reaching the cytosol. These findings led to the prediction that the bacterial PI-PLC promotes escape through the production of diacylglycerol leading to the activation of host PKCbeta. To test this hypothesis, bone marrow-derived macrophages (BMMf) obtained from PKCbeta knockout (PKCbetaKO) or C57Bl/6 mice were infected with L. monocytogenes. We observed that wild-type L. monocytogenes escapes from the phagosome of PKCbetaKO BMMf as well as from C57Bl/6 BMMf. However, in PKCbetaKO BMMf, L. monocytogenes uses a PI-PLC-independent, but phosphatidylcholine-preferring PLC (PC-PLC)-dependent pathway to facilitate escape. These findings strongly support the hypothesis that PI-PLC promotes escape through mobilization of host PKCbeta.
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Affiliation(s)
- Mathilde A Poussin
- Department of Microbiology, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6076, USA
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17
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Abstract
RACK1 (receptor for activated C kinase 1) is an abundant scaffolding protein, which binds active PKCbetaII (protein kinase C betaII) increasing its activity in vitro. RACK1 has also been described as a component of the small ribosomal subunit, in proximity to the mRNA exit channel. In the present study we tested the hypothesis that PKCbetaII plays a specific role in translational control and verified whether it may associate with the ribosomal machinery. We find that specific inhibition of PKCbetaI/II reduces translation as well as global PKC inhibition, but without affecting phosphorylation of mTOR (mammalian target of rapamycin) targets. These results suggest that PKCbetaII acts as a specific PKC isoform affecting translation in an mTOR-independent fashion, possibly close to the ribosomal machinery. Using far-Western analysis, we found that PKCbetaII binds ribosomes in vitro. Co-immunoprecipitation studies indicate that a small but reproducible pool of PKCbetaII is associated with membranes containing ribosomes, suggesting that in vivo PKCbetaII may also physically interact with the ribosomal machinery. Polysomal profiles show that stimulation of PKC results in an increased polysomes/80S ratio, associated with a shift of PKCbetaII to the heavier part of the gradient. A RACK1-derived peptide that inhibits the binding of active PKCbetaII to RACK1 reduces the polysomes/80S ratio and methionine incorporation, suggesting that binding of PKCbetaII to RACK1 is important for PKC-mediated translational control. Finally, down-regulation of RACK1 by siRNA (small interfering RNA) impairs the PKC-mediated increase of translation. Taken together the results of the present study show that PKCbetaII can act as a specific PKC isoform regulating translation, in an mTOR-independent fashion, possibly close to the ribosomal machinery.
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18
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Abstract
Protein kinase C (PKC) is a family of kinases that plays diverse roles in many cellular functions, notably proliferation, differentiation, and cell survival. PKC is processed by phosphorylation and regulated by cofactor binding and subcellular localization. Extensive detail is available on the molecular mechanisms that regulate the maturation, activation, and signaling of PKC. However, less information is available on how signaling is terminated both from a global perspective and isozyme-specific differences. To target PKC therapeutically, various ATP-competitive inhibitors have been developed, but this method has problems with specificity. One possible new approach to developing novel, specific therapeutics for PKC would be to target the signaling termination pathways of the enzyme. This review focuses on the new developments in understanding how PKC signaling is terminated and how current drug therapies as well as information obtained from the recent elucidation of various PKC structures and down-regulation pathways could be used to develop novel and specific therapeutics for PKC.
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Affiliation(s)
- Christine M. Gould
- Department of Pharmacology, University of California at San Diego, La Jolla, CA 92093-0721
| | - Alexandra C. Newton
- Department of Pharmacology, University of California at San Diego, La Jolla, CA 92093-0721
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19
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Dai Z, Dulyaninova NG, Kumar S, Bresnick AR, Lawrence DS. Visual snapshots of intracellular kinase activity at the onset of mitosis. ACTA ACUST UNITED AC 2008; 14:1254-60. [PMID: 18022564 DOI: 10.1016/j.chembiol.2007.10.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2007] [Revised: 10/03/2007] [Accepted: 10/04/2007] [Indexed: 10/22/2022]
Abstract
Visual snapshots of intracellular kinase activity can be acquired with exquisite temporal control by using a light-activatable (caged) sensor, thereby providing a means to interrogate enzymatic activity at any point during the cell-division cycle. Robust protein kinase activity transpires just prior to, but not immediately after, nuclear envelope breakdown (NEB). Furthermore, kinase activity is required for the progression from prophase into metaphase. Finally, the application of selective protein kinase C (PKC) inhibitors, in combination with the caged sensor, correlates the action of the PKC beta isoform with subsequent NEB.
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Affiliation(s)
- Zhaohua Dai
- Department of Biochemistry, The Albert Einstein College of Medicine of Yeshiva University, 1300 Morris Park Avenue, Bronx, NY 10461, USA
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20
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Slattery C, Ryan MP, McMorrow T. Protein kinase C beta overexpression induces fibrotic effects in human proximal tubular epithelial cells. Int J Biochem Cell Biol 2008; 40:2218-29. [DOI: 10.1016/j.biocel.2008.03.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2007] [Revised: 02/28/2008] [Accepted: 03/01/2008] [Indexed: 01/16/2023]
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21
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Takahashi H, Namiki H. Mechanism of membrane redistribution of protein kinase C by its ATP-competitive inhibitors. Biochem J 2007; 405:331-40. [PMID: 17373912 PMCID: PMC1904528 DOI: 10.1042/bj20070299] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
ATP-competitive inhibitors of PKC (protein kinase C) such as the bisindolylmaleimide GF 109203X, which interact with the ATP-binding site in the PKC molecule, have also been shown to affect several redistribution events of PKC. However, the reason why these inhibitors affect the redistribution is still controversial. In the present study, using immunoblot analysis and GFP (green fluorescent protein)-tagged PKC, we showed that, at commonly used concentrations, these ATP-competitive inhibitors alone induced redistribution of DAG (diacylglycerol)-sensitive PKCalpha, PKCbetaII, PKCdelta and PKCepsilon, but not atypical PKCzeta, to the endomembrane or the plasma membrane. Studies with deletion and point mutants showed that the DAG-sensitive C1 domain of PKC was required for membrane redistribution by these inhibitors. Furthermore, membrane redistribution was prevented by the aminosteroid PLC (phospholipase C) inhibitor U-73122, although an ATP-competitive inhibitor had no significant effect on acute DAG generation. Immunoblot analysis showed that an ATP-competitive inhibitor enhanced cell-permeable DAG analogue- or phorbol-ester-induced translocation of endogenous PKC. Furthermore, these inhibitors also enhanced [3H]phorbol 12,13-dibutyrate binding to the cytosolic fractions from PKCalpha-GFP-overexpressing cells. These results clearly demonstrate that ATP-competitive inhibitors cause redistribution of DAG-sensitive PKCs to membranes containing endogenous DAG by altering the DAG sensitivity of PKC and support the idea that the inhibitors destabilize the closed conformation of PKC and make the C1 domain accessible to DAG. Most importantly, our findings provide novel insights for the interpretation of studies using ATP-competitive inhibitors, and, especially, suggest caution about the interpretation of the relationship between the redistribution and kinase activity of PKC.
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Affiliation(s)
- Hideyuki Takahashi
- Department of Biology, School of Education, Waseda University, Shinjuku-ku, Tokyo 169-0051, Japan.
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22
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Kitatani K, Idkowiak-Baldys J, Hannun YA. Mechanism of inhibition of sequestration of protein kinase C alpha/betaII by ceramide. Roles of ceramide-activated protein phosphatases and phosphorylation/dephosphorylation of protein kinase C alpha/betaII on threonine 638/641. J Biol Chem 2007; 282:20647-56. [PMID: 17504762 DOI: 10.1074/jbc.m609162200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Sustained activation of protein kinase C (PKC) isoenzymes alpha and betaII leads to their translocation to a perinuclear region and to the formation of the pericentrion, a PKC-dependent subset of recycling endosomes. In MCF-7 human breast cancer cells, the action of the PKC activator 4beta-phorbol-12-myristate-13-acetate (PMA) evokes ceramide formation, which in turn prevents PKCalpha/betaII translocation to the pericentrion. In this study we investigated the mechanisms by which ceramide negatively regulates this translocation of PKCalpha/betaII. Upon PMA treatment, HEK-293 cells displayed dual phosphorylation of PKCalpha/betaII at carboxyl-terminal sites (Thr-638/641 and Ser-657/660), whereas in MCF-7 cells PKCalpha/betaII were phosphorylated at Ser-657/660 but not Thr-638/641. Inhibition of ceramide synthesis by fumonisin B1 overcame the defect in PKC phosphorylation and restored translocation of PKCalpha/betaII to the pericentrion. To determine the involvement of ceramide-activated protein phosphatases in PKC regulation, we employed small interference RNA to silence individual Ser/Thr protein phosphatases. Knockdown of isoforms alpha or beta of the catalytic subunits of protein phosphatase 1 not only increased phosphorylation of PKCalpha/betaII at Thr-638/641 but also restored PKCbetaII translocation to the pericentrion. Mutagenesis approaches in HEK-293 cells revealed that mutation of either Thr-641 or Ser-660 to Ala in PKCbetaII abolished sequestration of PKC, implying the indispensable roles of phosphorylation of PKCalpha/betaII at those sites for their translocation to the pericentrion. Reciprocally, a point mutation of Thr-641 to Glu, which mimics phosphorylation, in PKCbetaII overcame the inhibitory effects of ceramide on PKC translocation in PMA-stimulated MCF-7 cells. Therefore, the results demonstrate a novel role for carboxyl-terminal phosphorylation of PKCalpha/betaII in the translocation of PKC to the pericentrion, and they disclose specific regulation of PKC autophosphorylation by ceramide through the activation of specific isoforms of protein phosphatase 1.
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Affiliation(s)
- Kazuyuki Kitatani
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA
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23
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Idkowiak-Baldys J, Becker KP, Kitatani K, Hannun YA. Dynamic sequestration of the recycling compartment by classical protein kinase C. J Biol Chem 2006; 281:22321-22331. [PMID: 16751194 DOI: 10.1074/jbc.m512540200] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
It has been previously shown that upon sustained stimulation (30-60 min) with phorbol esters, protein kinase C (PKC) alpha and betaII become sequestered in a juxtanuclear region, the pericentrion. The activation of PKC also results in sequestration of transferrin, suggesting a role for PKC in regulating endocytosis and sequestration of recycling components. In this work we characterize the pericentrion as a PKC-dependent subset of the recycling compartment. We demonstrate that upon sustained stimulation of PKC, both protein (CD59, caveolin) and possibly also lipid (Bodipy-GM1) cargo become sequestered in a PKC-dependent manner. This sequestration displayed a strict temperature requirement and was inhibited below 32 degrees C. Treatment of cells with phorbol myristate acetate for 60 min led to the formation of a distinct membrane structure. PKC sequestration and pericentrion formation were blocked by hypertonic sucrose as well as by potassium depletion (inhibitors of clathrin-dependent endocytosis) but not by nystatin or filipin, which inhibit clathrin-independent pathways. Interestingly, it was also observed that some molecules that internalize through clathrin-independent pathways (CD59, Bodipy-GM1, caveolin) also sequestered to the pericentrion upon sustained PKC activation, suggesting that PKC acted distal to the site of internalization of endocytic cargo. Together these results suggest that PKC regulates sequestration of recycling molecules into this compartment, the pericentrion.
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Affiliation(s)
- Jolanta Idkowiak-Baldys
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Kevin P Becker
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Kazuyuki Kitatani
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Yusuf A Hannun
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425.
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24
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Hu T, Exton JH. A point mutation at phenylalanine 663 abolishes protein kinase Cα’s ability to translocate to the perinuclear region and activate phospholipase D1. Biochem Biophys Res Commun 2005; 333:750-3. [PMID: 15963950 DOI: 10.1016/j.bbrc.2005.05.184] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2005] [Accepted: 05/19/2005] [Indexed: 11/17/2022]
Abstract
Previous research showed that protein kinase C alpha (PKC alpha) translocated to the perinuclear region and activated phospholipase D1, but the mechanism involved was not clear. Here, we provide evidence that Phe 663 (the 10th amino acid from C-terminus) of PKC alpha is essential for its translocation. A point mutation (F663D) completely blocked PKC alpha's binding to and activation of phospholipase D1. Further studies showed that deletion of the C-terminal nine amino acids of PKC alpha did not alter its translocation to the perinuclear region but deletion of the C-terminal 10 amino acids and the F663D mutation abolished this translocation. The F663D mutant was found to be resistant to dephosphorylation, which might account for its inability to translocate to the perinuclear region and activate PLD1, since dephosphorylation of PKC alpha is required for its relocation from plasma membrane to the perinuclear region.
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Affiliation(s)
- Tianhui Hu
- Howard Hughes Medical Institute and Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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25
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Haberman Y, Ziv I, Gorzalczany Y, Fukuda M, Sagi-Eisenberg R. Classical protein kinase C(s) regulates targeting of synaptotagmin IX to the endocytic recycling compartment. J Cell Sci 2005; 118:1641-9. [PMID: 15784685 DOI: 10.1242/jcs.02276] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Neuronal and non-neuronal tissues show distinctly different intracellular localization of synaptotagmin (Syt) homologues. Therefore, cell type-specific mechanisms are likely to direct Syt homologues to their final cellular destinations. Syt IX localizes to dense core vesicles in PC12 cells. However, in the rat basophilic leukemia (RBL-2H3) mast cell line, as well as in CHO cells, Syt IX is localized at the endocytic recycling compartment (ERC). We show that targeting of Syt IX to the ERC involves constitutive trafficking to the plasma membrane followed by internalization and transport to the ERC. We further show that internalization from the plasma membrane and delivery to the ERC are dependent on phosphorylation by Ca(2+)-dependent protein kinase Calpha or beta. As such, correct targeting of Syt IX is facilitated by the phorbol ester TPA but prevented by the cPKC inhibitor Go 6976.
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Affiliation(s)
- Yael Haberman
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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26
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Becker KP, Kitatani K, Idkowiak-Baldys J, Bielawski J, Hannun YA. Selective Inhibition of Juxtanuclear Translocation of Protein Kinase C βII by a Negative Feedback Mechanism Involving Ceramide Formed from the Salvage Pathway. J Biol Chem 2005; 280:2606-12. [PMID: 15546881 DOI: 10.1074/jbc.m409066200] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In a previous study, we showed that protein kinase C betaII (PKC betaII) translocated to a novel juxtanuclear compartment as observed in several cell types (Becker, K. P., and Hannun, Y. A. (2003) J. Biol. Chem. 278, 52747-52754). In this study, we noted the absence of this translocation in MCF-7 breast cancer cells, and we examined the mechanisms underlying this selectivity of response. We show that sustained stimulation of PKC betaII with 4beta-phorbol 12-myristate 13-acetate (PMA) resulted in accumulation of ceramide in MCF-7 cells but not in those cells that showed juxtanuclear translocation of PKC betaII. Addition of exogenous ceramides or formation of endogenous ceramide by the action of bacterial sphingomyelinase prevented PMA-induced translocation of PKC betaII in HEK 293 cells. On the other hand, inhibition of ceramide accumulation with fumonisin B1 restored the ability of PMA to induce translocation of PKC betaII in MCF-7 cells. Taken together, the results showed that endogenous ceramide is both necessary and sufficient for preventing juxtanuclear translocation of PKC betaII in response to PMA. Investigation of the mechanisms of ceramide generation in response to PMA revealed that PMA activated the salvage pathway of ceramide formation and not the de novo pathway. This conclusion was based on the following: 1) the ability of fumonisin B1 but not myriocin to inhibit ceramide formation, 2) the ability of PMA to induce increases in palmitate-labeled ceramide only under chase labeling but not acute pulse labeling, 3) the induction of the levels of sphingosine but not dihydrosphingosine in response to PMA, and 4) induction of sphingomyelin hydrolysis in response to PMA. Together, these results define a novel pathway of regulated formation of ceramide, the salvage pathway, and they define a role for this pathway in regulating juxtanuclear translocation of PKC betaII.
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Affiliation(s)
- Kevin P Becker
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
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