Phosphoinositide 3-kinase-dependent regulation of phospholipase Cγ

2007 ◽  
Vol 35 (2) ◽  
pp. 229-230 ◽  
Author(s):  
T. Maffucci ◽  
M. Falasca
Keyword(s):  
Phospholipase C ◽  
Tyrosine Kinases ◽  
Receptor Tyrosine Kinases ◽  
Second Messengers ◽  
Pleckstrin Homology Domain ◽  
Ph Domain ◽  
Pleckstrin Homology ◽  
Functional Roles ◽  
Phosphoinositide 3 Kinase

Activation of the enzyme PLC (phospholipase C) leads to the formation of second messengers Ins(1,4,5)P3 and diacylglycerol. RTKs (receptor tyrosine kinases) activate this reaction through PLCγ isoenzymes. It has been shown that PI3K (phosphoinositide 3-kinase) may regulate PLCγ activity through the interaction of PI3K product PtdIns(3,4,5)P3 and the PLCγ PH domain (pleckstrin homology domain). Here, we analyse the potential functional roles of the PI3K/PLC pathway.

scholarly journals Substitution of the myristoylation signal of human immunodeficiency virus type 1 Pr55Gag with the phospholipase C-δ1 pleckstrin homology domain results in infectious pseudovirion production

2008 ◽  
Vol 89 (12) ◽  
pp. 3144-3149 ◽  
Author(s):  
Emiko Urano ◽  
Toru Aoki ◽  
Yuko Futahashi ◽  
Tsutomu Murakami ◽  
Yuko Morikawa ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Phospholipase C ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Pleckstrin Homology Domain ◽  
Ph Domain ◽  
Pleckstrin Homology ◽  
Viral Production ◽  
Immunodeficiency Virus

The matrix domain (MA) of human immunodeficiency virus type 1 Pr55Gag is covalently modified with a myristoyl group that mediates efficient viral production. However, the role of myristoylation, particularly in the viral entry process, remains uninvestigated. This study replaced the myristoylation signal of MA with a well-studied phosphatidylinositol 4,5-biphosphate-binding plasma membrane (PM) targeting motif, the phospholipase C-δ1 pleckstrin homology (PH) domain. PH–Gag–Pol PM targeting and viral production efficiencies were improved compared with Gag–Pol, consistent with the estimated increases in Gag–PM affinity. Both virions were recovered in similar sucrose density-gradient fractions and had similar mature virion morphologies. Importantly, PH–Gag–Pol and Gag–Pol pseudovirions had almost identical infectivity, suggesting a dispensable role for myristoylation in the virus life cycle. PH–Gag–Pol might be useful in separating the myristoylation-dependent processes from the myristoylation-independent processes. This the first report demonstrating infectious pseudovirion production without myristoylated Pr55Gag.

Ceramide dissociates 3′-phosphoinositide production from pleckstrin homology domain translocation

2001 ◽  
Vol 354 (2) ◽  
pp. 359-368 ◽  
Author(s):  
Suzanne STRATFORD ◽  
Daryll B. DEWALD ◽  
Scott A. SUMMERS
Keyword(s):  
Growth Factor ◽  
Binding Proteins ◽  
Cellular Proliferation ◽  
Pleckstrin Homology Domain ◽  
Ph Domain ◽  
Pleckstrin Homology ◽  
Lipid Kinase ◽  
Ph Domains ◽  
Phosphoinositide 3 Kinase ◽  
Synthase Inhibitor

Numerous hormones, cytokines and transforming oncogenes activate phosphoinositide 3-kinase (PI-3K), a lipid kinase that initiates signal transduction cascades regulating cellular proliferation, survival, protein synthesis and glucose metabolism. PI-3K catalyses the production of the 3′-phosphoinositides PtdIns(3,4)P2 and PtdIns(3,4,5)P3, which recruit downstream effector enzymes to the membrane via their pleckstrin homology (PH) domains. Recent studies have indicated that another signalling lipid, the sphingolipid ceramide, inhibits several PI-3K-dependent events, including insulin-stimulated glucose uptake and growth-factor-stimulated cell survival. Here we show that ceramide analogues specifically prevent the recruitment of the PtdIns(3,4,5)P3-binding proteins Akt/protein kinase B (PKB) or the general receptor for phosphoinositides-1 (GRP1). Specifically, the short-chain ceramide derivative C2-ceramide inhibited the platelet-derived growth factor (PDGF)-stimulated translocation of full-length Akt/PKB, as well as truncated proteins encoding only the PH domains of Akt/PKB or GRP1. C2-ceramide did not alter the membrane localization of the PH domain for phospholipase Cδ, which preferentially binds PtdIns(4,5)P2, nor did it affect the PDGF-stimulated production of PtdIns(3,4)P2 or PtdIns(3,4,5)P3. Interestingly, a glucosylceramide synthase inhibitor, 1-phenyl-2-decanoylamino-3-morpholinopropan-1-ol (PDMP), shown previously to increase intracellular ceramide concentrations without affecting PI-3K [Rani, Abe, Chang, Rosenzweig, Saltiel, Radin and Shayman (1995) J. Biol. Chem. 270, 2859–2867], recapitulated the inhibitory effects of C2-ceramide on PDGF-stimulated Akt/PKB phosphorylation. These studies indicate that ceramide prevents the translocation of certain PtdIns(3,4,5)P3-binding proteins, despite the presence of a full complement of PtdIns(3,4)P2 or PtdIns(3,4,5)P3. Furthermore, these findings suggest a mechanism by which stimuli that induce ceramide synthesis could negate the fundamental signalling pathways initiated by PI-3K.

scholarly journals Lipid-targeting pleckstrin homology domain turns its autoinhibitory face toward the TEC kinases

2019 ◽  
Vol 116 (43) ◽  
pp. 21539-21544 ◽  
Author(s):  
Neha Amatya ◽  
Thomas E. Wales ◽  
Annie Kwon ◽  
Wayland Yeung ◽  
Raji E. Joseph ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Kinases ◽  
Kinase Domain ◽  
Pleckstrin Homology Domain ◽  
Activation Loop ◽  
Ph Domain ◽  
Pleckstrin Homology ◽  
Sequence Comparisons ◽  
Exchange Mass Spectrometry ◽  
Tec Kinases

The pleckstrin homology (PH) domain is well known for its phospholipid targeting function. The PH-TEC homology (PHTH) domain within the TEC family of tyrosine kinases is also a crucial component of the autoinhibitory apparatus. The autoinhibitory surface on the PHTH domain has been previously defined, and biochemical investigations have shown that PHTH-mediated inhibition is mutually exclusive with phosphatidylinositol binding. Here we use hydrogen/deuterium exchange mass spectrometry, nuclear magnetic resonance (NMR), and evolutionary sequence comparisons to map where and how the PHTH domain affects the Bruton’s tyrosine kinase (BTK) domain. The data map a PHTH-binding site on the activation loop face of the kinase C lobe, suggesting that the PHTH domain masks the activation loop and the substrate-docking site. Moreover, localized NMR spectral changes are observed for non–surface-exposed residues in the active site and on the distal side of the kinase domain. These data suggest that the association of PHTH induces allosteric conformational shifts in regions of the kinase domain that are critical for catalysis. Through statistical comparisons of diverse tyrosine kinase sequences, we identify residues unique to BTK that coincide with the experimentally determined PHTH-binding surface on the kinase domain. Our data provide a more complete picture of the autoinhibitory conformation adopted by full-length TEC kinases, creating opportunities to target the regulatory domains to control the function of these kinases in a biological setting.

scholarly journals Membrane activity of the phospholipase C-δ1 pleckstrin homology (PH) domain

2005 ◽  
Vol 389 (2) ◽  
pp. 435-441 ◽  
Author(s):  
Frits M. Flesch ◽  
Jong W. Yu ◽  
Mark A. Lemmon ◽  
Koert N. J. Burger
Keyword(s):  
Binding Site ◽  
Phospholipase C ◽  
Membrane Surface ◽  
Pleckstrin Homology Domain ◽  
Membrane Insertion ◽  
Ph Domain ◽  
Pleckstrin Homology ◽  
Lipid Mixture ◽  
Membrane Activity ◽  
Binding Domains

PH-PLCδ1 [the PH domain (pleckstrin homology domain) of PLCδ1 (phospholipase C-δ1)] is among the best-characterized phosphoinositide-binding domains. PH-PLCδ1 binds with high specificity to the headgroup of PtdIns(4,5)P2, but little is known about its interfacial properties. In the present study, we show that PH-PLCδ1 is also membrane-active and can insert significantly into PtdIns(4,5)P2-containing monolayers at physiological (bilayer-equivalent) surface pressures. However, this membrane activity appears to involve interactions distinct from those that target PH-PLCδ1 to the PtdIns(4,5)P2 headgroup. Whereas the majority of PtdIns(4,5)P2-bound PH-PLCδ1 can be displaced by adding excess of soluble headgroup [Ins(1,4,5)P3], membrane activity of PH-PLCδ1 cannot. PH-PLCδ1 differs from other phosphoinositide-binding domains in that its membrane insertion does not require that the phosphoinositide-binding site be occupied. Significant monolayer insertion remains when the phosphoinositide-binding site is mutated, and PH-PLCδ1 can insert into monolayers that contain no PtdIns(4,5)P2 at all. Our results suggest a model in which reversible membrane binding of PH-PLCδ1, mediated by PtdIns(4,5)P2 or other acidic phospholipids, occurs without membrane insertion. Accumulation of the PH domain at the membrane surface enhances the efficiency of insertion, but does not significantly affect its extent, whereas the presence of phosphatidylethanolamine and cholesterol in the lipid mixture promotes the extent of insertion. This is the first report of membrane activity in an isolated PH domain and has implications for understanding the membrane targeting by this common type of domain.

Stratifin, a keratinocyte specific 14–3-3 protein, harbors a pleckstrin homology (PH) domain and enhances protein kinase C activity

1995 ◽  
Vol 108 (11) ◽  
pp. 3569-3579
Author(s):  
E. Dellambra ◽  
M. Patrone ◽  
B. Sparatore ◽  
A. Negri ◽  
F. Ceciliani ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Terminal Differentiation ◽  
Pleckstrin Homology Domain ◽  
Ph Domain ◽  
Pleckstrin Homology ◽  
Protein Database ◽  
Kinase C ◽  
Human Keratinocyte ◽  
Protein Kinase C Activity

The intrinsic signal(s) responsible for the onset of human keratinocyte terminal differentiation is not yet fully understood. Evidence has been recently accumulated linking the phospholipase-mediated activation of protein kinase C to the coordinate changes in gene expression occurring during keratinocyte terminal differentiation. Here we report the purification of a keratinocyte-derived protein enhancing protein kinase C enzymatic activity. The stimulator eluted as a peak with estimated molecular mass of approximately 70 kDa, while analysis by SDS-PAGE showed a 30 kDa protein migrating as a distinct doublet, suggesting the formation of a 30 kDa homodimer. The amino acid sequence analysis allowed the unambigous identification of the protein kinase C stimulator as a mixture of the highly homologous sigma (stratifin) and zeta isoforms of 14–3-3 proteins, which are homodimers of identical 30 kDa subunits. Mono Q anion exchange chromatography and immunoblot analysis further confirmed that stratifin enhances protein kinase C activity. Stratifin was originally sequenced from a human keratinocyte protein database, but its function was unknown. The pleckstrin homology domain has been recently related to protein translocation to the cell membrane as well as to functional interactions of intracellular proteins involved in signal transduction. We show here that stratifin (and 14–3-3 zeta) harbors a pleckstrin homology domain, and the consequent functional implications will be discussed.

scholarly journals Role of TAPP1 and TAPP2 adaptor binding to PtdIns(3,4)P2 in regulating insulin sensitivity defined by knock-in analysis

2011 ◽  
Vol 434 (2) ◽  
pp. 265-274 ◽  
Author(s):  
Stephan Wullschleger ◽  
David H. Wasserman ◽  
Alex Gray ◽  
Kei Sakamoto ◽  
Dario R. Alessi
Keyword(s):  
Insulin Sensitivity ◽  
Insulin Signalling ◽  
Adaptor Proteins ◽  
Whole Body ◽  
Pleckstrin Homology Domain ◽  
Ph Domain ◽  
Enhanced Production ◽  
Pi3k Signalling ◽  
Inositol Phosphatases ◽  
Phosphoinositide 3 Kinase

Insulin sensitivity is critically dependent on the activity of PI3K (phosphoinositide 3-kinase) and generation of the PtdIns(3,4,5)P3 second messenger. PtdIns(3,4,5)P3 can be broken down to PtdIns(3,4)P2 through the action of the SHIPs (Src-homology-2-domain-containing inositol phosphatases). As PtdIns(3,4)P2 levels peak after those of PtdIns(3,4,5)P3, it has been proposed that PtdIns(3,4)P2 controls a negative-feedback loop that down-regulates the insulin and PI3K network. Previously, we identified two related adaptor proteins termed TAPP [tandem PH (pleckstrin homology)-domain-containing protein] 1 and TAPP2 that specifically bind to PtdIns(3,4)P2 through their C-terminal PH domain. To determine whether TAPP1 and TAPP2 play a role in regulating insulin sensitivity, we generated knock-in mice that express normal endogenous levels of mutant TAPP1 and TAPP2 that are incapable of binding PtdIns(3,4)P2. These homozygous TAPP1R211L/R211LTAPP2R218L/R218L double knock-in mice are viable and exhibit significantly enhanced activation of Akt, a key downstream mediator of insulin signalling. Consistent with increased PI3K and Akt activity, the double knock-in mice display enhanced whole body insulin sensitivity and disposal of glucose uptake into muscle tissues. We also generated wild-type and double TAPP1R211L/R211LTAPP2R218L/R218L knock-in embryonic fibroblasts and found that insulin triggered enhanced production of PtdIns(3,4,5)P3 and Akt activity in the double knock-in fibroblasts. These observations provide the first genetic evidence to support the notion that binding of TAPP1 and TAPP2 adap-tors to PtdIns(3,4)P2 function as negative regulators of the insulin and PI3K signalling pathways.

scholarly journals Interaction of Elongation Factor-1α and Pleckstrin Homology Domain of Phospholipase C-γ1 with Activating Its Activity

2002 ◽  
Vol 277 (22) ◽  
pp. 19697-19702 ◽  
Author(s):  
Jong-Soo Chang ◽  
Heon Seok ◽  
Taeg-Kyu Kwon ◽  
Do Sik Min ◽  
Bong-Hyun Ahn ◽  
...  
Keyword(s):  
Phospholipase C ◽  
Elongation Factor ◽  
Pleckstrin Homology Domain ◽  
Pleckstrin Homology ◽  
Elongation Factor 1Α

scholarly journals Influence of membrane curvature on the structure of the membrane-associated pleckstrin homology domain of phospholipase C-δ1

2009 ◽  
Vol 1788 (12) ◽  
pp. 2575-2583 ◽  
Author(s):  
Naoko Uekama ◽  
Takahiro Aoki ◽  
Toshihiro Maruoka ◽  
Seiji Kurisu ◽  
Akiko Hatakeyama ◽  
...  
Keyword(s):  
Phospholipase C ◽  
Membrane Curvature ◽  
Pleckstrin Homology Domain ◽  
Pleckstrin Homology
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