ROLE AND REGULATION OF PROTEIN KINASE C ISOENZYMES

Summary

Principal Investigator: Yusuf Awni Hannun
Abstract: DESCRIPTION (provided by applicant): Protein kinase C (PKC) has served as the prototype of lipid-regulated enzymes, especially in the case of the phosphatidylinositol (PI) cycle whereby PI-derived diacylglycerol (DAG) serves as the direct activator of PKC. Given the rapid turnover of the PI cycle (within 90 seconds of receptor engagement), this paradigm of PKC activation has by necessity focused on the very acute phase of PKC regulation. Importantly, this paradigm does not address other mechanisms of DAG generation, most notably through phospholipase D (PLD), it does not distinguish mechanisms for regulating activation of specific isoenzymes, and it focuses only on the plasma membrane as a site for PKC action. Extensive results (obtained during the past 5 years) as well as ongoing results have generated exciting information on novel mechanisms and functions of PKC involving translocation of PKC to a novel juxtanuclear/pericentriolar compartment. This novel process requires sustained activation of PKC (30-60 min) in response to ligands of G-protein-coupled receptors (and phorbol esters), and it requires continuous activation of PKC as well as PLD (unlike the acute translocation of PKC to the PM). Functionally, receptor activation leads not only to the translocation of the receptor itself to this juxtanuclear compartment (which has features of a previously-identified but not well-appreciated component of slow recycling endosomes), but also the co-translocation of many other plasma membrane/recycling receptors, channels, other proteins and lipids. Moreover, very recent evidence is beginning to point to active signaling in this novel compartment. Based on these observations, we hypothesize that receptor-induced sustained activation of PKCa/ssII induces the formation of this novel pericentriolar endocytic compartment in a PKC and PLD- dependent manner. This mechanism plays a key role in receptor sequestration and in the regulation of cross- sequestration of other receptors and PM proteins, and may initiate novel signaling in this compartment. This hypothesis will be investigated by pursuing the following specific aims 1) Define and establish ligand- induced novel translocation of receptors and formation of this novel compartment, 'the pericentrion';2) Define roles of receptor-induced and PKC/PLD-mediated pericentrion formation in sequestration of recycling components, their fate, and their function;and 3) Define roles of receptor-induced and PKC/PLD-mediated pericentrion formation in signaling. The proposed and ongoing studies are defining a novel compartment, novel functions of receptors in regulating endocytic trafficking, and the possibility of a novel PKC/PLD signaling compartment. If correct, this novel regulated process may be involved in multiple physiologic and pathophysiologic processes that depend on availability of key proteins and/or lipids at the PM, including regulation of smooth muscles and endothelial cells, both of great importance to vascular biology. PUBLIC HEALTH RELEVANCE: Membrane receptors are critical proteins that serve as targets for many natural compounds (e.g. serotonin, adrenaline, dopamine, and angiotensin) as well as pharmacologic agents important for blood pressure regulation, blood clotting, gastric ulcers and stomach acidity, treatment of depression, and other diseases). We have discovered that sustained stimulation of some of these receptors can result in profound changes in how the cell handles the distribution and function of many other receptors and key proteins. We are defining the significance and mechanisms by which this process occurs and is regulated. In particular we focus on a key signaling protein known as protein kinase C (PKC) and its activating lipids.
Funding Period: 1990-07-01 - 2015-03-31
more information: NIH RePORT

Top Publications

  1. ncbi Sphingosine kinase: biochemical and cellular regulation and role in disease
    Tarek Assad Taha
    Department of Medicine, Medical University of South Carolina, USA
    J Biochem Mol Biol 39:113-31. 2006
  2. ncbi Dynamic sequestration of the recycling compartment by classical protein kinase C
    Jolanta Idkowiak-Baldys
    Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
    J Biol Chem 281:22321-31. 2006
  3. ncbi 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
    Kazuyuki Kitatani
    Department of Biochemistry and Molecular Biology, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA
    J Biol Chem 282:20647-56. 2007
  4. pmc Sustained receptor stimulation leads to sequestration of recycling endosomes in a classical protein kinase C- and phospholipase D-dependent manner
    Jolanta Idkowiak-Baldys
    Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA
    J Biol Chem 284:22322-31. 2009
  5. pmc A novel mechanism of lysosomal acid sphingomyelinase maturation: requirement for carboxyl-terminal proteolytic processing
    Russell W Jenkins
    Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
    J Biol Chem 286:3777-88. 2011
  6. pmc Delayed phosphorylation of classical protein kinase C (PKC) substrates requires PKC internalization and formation of the pericentrion in a phospholipase D (PLD)-dependent manner
    Mohamad A El-Osta
    Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
    J Biol Chem 286:19340-53. 2011
  7. pmc Sustained PKCβII activity confers oncogenic properties in a phospholipase D- and mTOR-dependent manner
    Mohamad El Osta
    2Stony Brook Cancer Center and Department of Medicine, Stony Brook University, 100 Nicolls Rd, Stony Brook, NY 11794, USA
    FASEB J 28:495-505. 2014
  8. pmc Sustained activation of protein kinase C induces delayed phosphorylation and regulates the fate of epidermal growth factor receptor
    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
    PLoS ONE 8:e80721. 2013

Research Grants

Detail Information

Publications8

  1. ncbi Sphingosine kinase: biochemical and cellular regulation and role in disease
    Tarek Assad Taha
    Department of Medicine, Medical University of South Carolina, USA
    J Biochem Mol Biol 39:113-31. 2006
    ..This review is geared at mechanisms of regulation of sphingosine kinase and the coming to light of its role in disease...
  2. ncbi Dynamic sequestration of the recycling compartment by classical protein kinase C
    Jolanta Idkowiak-Baldys
    Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
    J Biol Chem 281:22321-31. 2006
    ..Together these results suggest that PKC regulates sequestration of recycling molecules into this compartment, the pericentrion...
  3. ncbi 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
    Kazuyuki Kitatani
    Department of Biochemistry and Molecular Biology, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA
    J Biol Chem 282:20647-56. 2007
    ....
  4. pmc Sustained receptor stimulation leads to sequestration of recycling endosomes in a classical protein kinase C- and phospholipase D-dependent manner
    Jolanta Idkowiak-Baldys
    Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA
    J Biol Chem 284:22322-31. 2009
    ..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...
  5. pmc A novel mechanism of lysosomal acid sphingomyelinase maturation: requirement for carboxyl-terminal proteolytic processing
    Russell W Jenkins
    Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
    J Biol Chem 286:3777-88. 2011
    ..Taken together, these results demonstrate that mature L-SMase arises from C-terminal proteolytic processing of pro-aSMase and suggest that impaired C-terminal proteolysis may lead to severe defects in L-SMase function...
  6. pmc Delayed phosphorylation of classical protein kinase C (PKC) substrates requires PKC internalization and formation of the pericentrion in a phospholipase D (PLD)-dependent manner
    Mohamad A El-Osta
    Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
    J Biol Chem 286:19340-53. 2011
    ..These results reveal an important role for PKC internalization and for the pericentrion as key determinants/amplifiers of PKC action...
  7. pmc Sustained PKCβII activity confers oncogenic properties in a phospholipase D- and mTOR-dependent manner
    Mohamad El Osta
    2Stony Brook Cancer Center and Department of Medicine, Stony Brook University, 100 Nicolls Rd, Stony Brook, NY 11794, USA
    FASEB J 28:495-505. 2014
    ....
  8. pmc Sustained activation of protein kinase C induces delayed phosphorylation and regulates the fate of epidermal growth factor receptor
    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
    PLoS ONE 8:e80721. 2013
    ..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. ..

Research Grants30

  1. Mechanism of Desensitization of Perivascular Nerve Ca2+-sensing Receptor Signalin
    EMMANUEL MODESTO AWUMEY; Fiscal Year: 2013
    ..In addition, the proposed studies will provide training opportunities for under-represented minority students at NCCU and prepare them for future careers in biomedical research. ..
  2. RAGE and Mechanisms of Vascular Dysfunction
    Shi Fang Yan; Fiscal Year: 2013
    ..Using novel and state-of-the-art techniques, floxed mice and molecular approaches to gene regulation, we are well-positioned to lead the study of RAGE in the next cycle of this Program. ..
  3. NHERF-1 and dopamine-mediated regulation of renal phosphate transport.
    Edward J Weinman; Fiscal Year: 2013
    ..abstract_text> ..
  4. TSH RECEPTOR MULTIMERIZATION
    TERRY FRANCIS DAVIES; Fiscal Year: 2013
    ....
  5. TRP Channel-Dependent Regulation of Arterial Tone
    Scott Earley; Fiscal Year: 2013
    ..abstract_text> ..
  6. Structure and Function of Neurotransmitter Transporters
    Harel Weinstein; Fiscal Year: 2013
    ....