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Shivaji A Thorat,
Dong Wook Kang,
Hyungchul Ryu,
Myeong Seop Kim,
Ho Shin Kim,
Jihyae Ann,
Taehwan Ha,
Sung-Eun Kim,
Karam Son,
Sun Choi, Peter M Blumberg,
Robert Frank,
Gregor Bahrenberg,
Klaus Schiene,
Thomas Christoph,
Jeewoo Lee
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ABSTRACT: The structure activity relationships of 2-oxy pyridine derivatives in the C-region of N-(6-trifluoromethyl-pyridin-3-ylmethyl) 2-(3-fluoro-4-methylsulfonylaminophenyl)propanamides as hTRPV1 antagonists were investigated. The analysis indicated that the lipophilicity of the 2-oxy substituents was critical for potent antagonism and 4 or 5 carbons appeared to be optimal for activity. Multiple compounds proved to have comparable activity to 1, which had been reported as the most potent antagonist for capsaicin activity among the previous series of compounds. Further analysis of compounds 22 (2-isobutyloxy) and 53 (2-benzyloxy) in the formalin test in mice demonstrated strong analgesic activity with full efficacy. Docking analysis of 53S using our hTRPV1 homology model indicated that the A- and B-region 2-(3-fluoro-4-methylsulfonylaminophenyl)propanamide made important hydrophobic and hydrogen bonding interactions with Tyr511 and that the C-region 6-trifluoromethyl and 2-benzyloxy groups of pyridine occupied the two hydrophobic binding pockets, respectively.
European journal of medicinal chemistry 04/2013; 64C:589-602. · 3.27 Impact Factor
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Noemi Kedei,
Nancy E Lewin,
Tamás Géczy,
Julia Selezneva,
Derek C Braun,
Jinqiu Chen,
Michelle A Herrmann,
Madeleine R Heldman,
Langston Lim,
Poonam Mannan,
Susan H Garfield,
Yam B Poudel,
Thomas J Cummins,
Arnab Rudra, Peter M Blumberg,
Gary E Keck
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ABSTRACT: The bryostatins are a group of 20 macrolides isolated by Pettit and co-workers from the marine organism Bugula neritina. Bryostatin 1, the flagship member of the family, has been the subject of intense chemical and biological investigations due to its remarkably diverse biological activities, including promising indications as therapy for cancer, Alzheimer's disease, and HIV. Other bryostatins, however, have attracted far less attention, most probably due to their relatively low natural abundance and associated scarcity of supply. Among all macrolides in this family, bryostatin 7 is biologically the most potent protein kinase C (PKC) ligand (in terms of binding affinity) and also the first bryostatin to be synthesized in the laboratory. Nonetheless, almost no biological studies have been carried out on this agent. We describe herein the total synthesis of bryostatin 7 based on our pyran annulation technology, which allows for the first detailed biological characterizations of bryostatin 7 with side-by-side comparisons to bryostatin 1. The results suggest that the more easily synthesized and less lipophilic bryostatin 7 may be an effective surrogate for bryostatin 1.
ACS Chemical Biology 02/2013; · 6.45 Impact Factor
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Myeong Seop Kim,
Hyungchul Ryu,
Dong Wook Kang,
Seong-Hee Cho,
Sejin Seo,
Young Soo Park,
Mi-Yeon Kim,
Eun Joo Kwak,
Yong Soo Kim,
Rahul S Bhondwe, [......],
Ian A Deandrea-Lazarus,
Larry V Pearce, Peter M Blumberg,
Robert Frank,
Gregor Bahrenberg,
Hannelore Stockhausen,
Babette Y Kögel,
Klaus Schiene,
Thomas Christoph,
Jeewoo Lee
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ABSTRACT: A series of N-(2-amino-6-trifluoromethylpyridin-3-ylmethyl)-2-(3-fluoro-4-methylsulfonylaminophenyl)propanamides were designed combining previously identified pharmacophoric elements and evaluated as hTRPV1 antagonists. The SAR analysis indicated that specific hydrophobic interactions of the 2-amino substituents in the C-region of the ligand were critical for high hTRPV1 binding potency. In particular, compound 49S was an excellent TRPV1 antagonist (K(i(CAP)) = 0.2 nM; IC(50(pH)) = 6.3 nM) and was thus approximately 100- and 20-fold more potent, respectively, than the parent compounds 2 and 3 for capsaicin antagonism. Furthermore, it demonstrated strong analgesic activity in the rat neuropathic model superior to 2 with almost no side effects. Compound 49S antagonized capsaicin induced hypothermia in mice but showed TRPV1-related hyperthermia. The basis for the high potency of 49S compared to 2 is suggested by docking analysis with our hTRPV1 homology model in which the 4-methylpiperidinyl group in the C-region of 49S made additional hydrophobic interactions with the hydrophobic region.
Journal of Medicinal Chemistry 09/2012; 55(19):8392-408. · 4.80 Impact Factor
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ABSTRACT: A series of TRPV1 agonists with amide, reverse amide, and thiourea groups in the B-region and their corresponding α-methylated analogues were investigated. Whereas the α-methylation of the amide B-region enhanced the binding affinities and potencies as agonists, that of the reverse amide and thiourea led to a reduction in receptor affinity. The analysis indicated that proper hydrogen bonding as well as steric effects in the B-region are critical for receptor binding.
Bioorganic & medicinal chemistry letters 06/2012; 22(16):5227-31. · 2.65 Impact Factor
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ABSTRACT: The role of the C(8) gem-dimethyl group in the A-ring of bryostatin 1 has been examined through chemical synthesis and biological evaluation of a new analogue. Assays for biological function using U937, K562, and MV4-11 cells as well as the profiles for downregulation of PKC isozymes revealed that the presence of this group is not a critical determinant for the unique pattern of biological activity of bryostatin.
Bioorganic & medicinal chemistry letters 04/2012; 22(12):4084-8. · 2.65 Impact Factor
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Rahul S Bhondwe,
Dong Wook Kang,
Myeong Seop Kim,
Ho Shin Kim,
Seul-gi Park,
Karam Son,
Sun Choi,
Krystle A Lang Kuhs,
Vladimir A Pavlyukovets,
Larry V Pearce, Peter M Blumberg,
Jeewoo Lee
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ABSTRACT: The structure-activity relationships of N-(3-acyloxy-2-benzylpropyl)-N'-4-[(methylsulfonylamino)benzyl] thioureas, which represent simplified RTX-based vanilloids, were investigated by varying the distances between the four principal pharmacophores and assessing binding and antagonistic activity on rTRPV1. The analysis indicated that a 3-pivaloyloxy-2-benzylpropyl C-region conferred the best potency in binding affinity and antagonism. The molecular modeling of this best template with the tetrameric homology model of rTRPV1 was performed to identify its binding interactions with the receptor.
Bioorganic & medicinal chemistry letters 04/2012; 22(11):3656-60. · 2.65 Impact Factor
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Tamas Geczy,
Megan L Peach,
Saïd El Kazzouli,
Dina M Sigano,
Ji-Hye Kang,
Christopher J Valle,
Julia Selezneva,
Wonhee Woo,
Noemi Kedei,
Nancy E Lewin,
Susan H Garfield,
Langston Lim,
Poonam Mannan,
Victor E Marquez, Peter M Blumberg
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ABSTRACT: C1 domains, the recognition motif of the second messenger diacylglycerol and of the phorbol esters, are classified as typical (ligand-responsive) or atypical (not ligand-responsive). The C1 domain of Vav1, a guanine nucleotide exchange factor, plays a critical role in regulation of Vav activity through stabilization of the Dbl homology domain, which is responsible for exchange activity of Vav. Although the C1 domain of Vav1 is classified as atypical, it retains a binding pocket geometry homologous to that of the typical C1 domains of PKCs. This study clarifies the basis for its failure to bind ligands. Substituting Vav1-specific residues into the C1b domain of PKCδ, we identified five crucial residues (Glu(9), Glu(10), Thr(11), Thr(24), and Tyr(26)) along the rim of the binding cleft that weaken binding potency in a cumulative fashion. Reciprocally, replacing these incompatible residues in the Vav1 C1 domain with the corresponding residues from PKCδ C1b (δC1b) conferred high potency for phorbol ester binding. Computer modeling predicts that these unique residues in Vav1 increase the hydrophilicity of the rim of the binding pocket, impairing membrane association and thereby preventing formation of the ternary C1-ligand-membrane binding complex. The initial design of diacylglycerol-lactones to exploit these Vav1 unique residues showed enhanced selectivity for C1 domains incorporating these residues, suggesting a strategy for the development of ligands targeting Vav1.
Journal of Biological Chemistry 02/2012; 287(16):13137-58. · 4.77 Impact Factor
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Wei Sun,
Keliang Liu,
HyungChul Ryu,
Dong Wook Kang,
Yong Soo Kim,
Myeong Seop Kim,
Yongsung Cho,
Rahul S Bhondwe,
Shivaji A Thorat,
Ho Shin Kim,
Larry V Pearce,
Vladimir A Pavlyukovets,
Richard Tran,
Matthew A Morgan,
Jozsef Lazar,
Christopher B Ryder,
Attila Toth, Peter M Blumberg,
Jeewoo Lee
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ABSTRACT: On the basis of the previous lead N-4-t-butylbenzyl 2-(3-fluoro-4-methylsulfonylaminophenyl) propanamide (3) as a potent TRPV1 antagonist, structure-activity relationships for the B (propanamide part) and C-region (4-t-butylbenzyl part) have been investigated for rTRPV1 in CHO cells. The B-region was modified with dimethyl, cyclopropyl and reverse amides and then the C-region was replaced with 4-substituted phenyl, aryl alkyl and diaryl alkyl derivatives. Among them, compound 50 showed high binding affinity with K(i)=21.5nM, which was twofold more potent than 3 and compound 54 exhibited potent antagonism with K(i(ant))=8.0nM comparable to 3.
Bioorganic & medicinal chemistry 02/2012; 20(3):1310-8. · 2.82 Impact Factor
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Yong Soo Kim,
Min-Jung Kil,
Sang-Uk Kang,
HyungChul Ryu,
Myeong Seop Kim,
Yongsung Cho,
Rahul S Bhondwe,
Shivaji A Thorat,
Wei Sun,
Keliang Liu,
Jin Hee Lee,
Sun Choi,
Larry V Pearce,
Vladimir A Pavlyukovets,
Matthew A Morgan,
Richard Tran,
Jozsef Lazar, Peter M Blumberg,
Jeewoo Lee
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ABSTRACT: Structure-activity relationships for the A-region in a series of N-4-t-butylbenzyl 2-(4-methylsulfonylaminophenyl) propanamides as TRPV1 antagonists have been investigated. Among them, the 3-fluoro analogue 54 showed high binding affinity and potent antagonism for both rTRPV1 and hTRPV1 in CHO cells. Its stereospecific activity was demonstrated with marked selectivity for the (S)-configuration (54S versus 54R). A docking study of 54S with our hTRPV1 homology model highlighted crucial hydrogen bonds between the ligand and the receptor contributing to its potency.
Bioorganic & medicinal chemistry 11/2011; 20(1):215-24. · 2.82 Impact Factor
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Noga Gal,
Sofiya Kolusheva,
Noemi Kedei,
Andrea Telek,
Taiyabah A Naeem,
Nancy E Lewin,
Langston Lim,
Poonam Mannan,
Susan H Garfield,
Saïd El Kazzouli,
Dina M Sigano,
Victor E Marquez, Peter M Blumberg,
Raz Jelinek
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ABSTRACT: N-methyl-substituted diacylglycerol-indololactones (DAG-indololactones) are newly synthesized effectors of protein kinase C (PKC) isoforms and exhibit substantial selectivity between RasGRP3 and PKCα. We present a comprehensive analysis of membrane interactions and biological activities of several DAG-indololactones. Translocation and binding activity assays underline significant variations between the PKC translocation characteristics affected by the ligands as compared to their binding activities. In parallel, the fluorescent properties of the ligands were employed for analysis of their membrane association profiles. Specifically, we found that a slight change in the linkage to the indole ring resulted in significant differences in membrane binding and association of the DAG-indololactones with lipid bilayers. Our analysis shows that seemingly small structural modifications of the hydrophobic regions of these biomimetic PKC effectors contribute to pronounced modulation of membrane interactions of the ligands.
ChemBioChem 10/2011; 12(15):2331-40. · 3.94 Impact Factor
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ABSTRACT: TRPV1 has emerged as a promising therapeutic target for pain as well as a broad range of other conditions such as asthma or urge incontinence. The identification of resiniferatoxin as an ultrapotent ligand partially able to dissect the acute activation of TRPV1 from subsequent desensitization and the subsequent intense efforts in medicinal chemistry have revealed that TRPV1 affords a dramatic landscape of opportunities for pharmacological manipulation. While agonism and antagonism have represented the primary directions for drug development, the pharmacological complexity of TRPV1 affords additional opportunities. Partial agonism/partial antagonism, its modulation by signaling pathways, variable desensitization, and slow kinetics of action can all be exploited through drug design.
Current topics in medicinal chemistry 06/2011; 11(17):2151-8. · 4.47 Impact Factor
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Noemi Kedei,
Emanuel Lubart,
Nancy E Lewin,
Andrea Telek,
Langston Lim,
Poonam Mannan,
Susan H Garfield,
Matthew B Kraft,
Gary E Keck,
Sofiya Kolusheva,
Raz Jelinek, Peter M Blumberg
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ABSTRACT: Phorbol 12-myristate 13-acetate (PMA) and bryostatin 1 are both potent protein kinase C (PKC) activators. In LNCaP human prostate cancer cells, PMA induces tumor necrosis factor alpha (TNFα) secretion and inhibits proliferation; bryostatin 1 does not, and indeed blocks the response to PMA. This difference has been attributed to bryostatin 1 not localizing PKCδ to the plasma membrane. Since phorbol ester lipophilicity influences PKCδ localization, we have examined in LNCaP cells a series of phorbol esters and related derivatives spanning some eight logs in lipophilicity (logP) to see if any behave like bryostatin 1. The compounds showed marked differences in their effects on proliferation and TNFα secretion. For example, maximal responses for TNFα secretion relative to PMA ranged from 97 % for octyl-indolactam V to 24 % for phorbol 12,13-dibenzoate. Dose-response curves ranged from monophasic for indolactam V to markedly biphasic for sapintoxin D. The divergent patterns of response, however, correlated neither to lipophilicity, to plasma membrane translocation of PKCδ, nor to the ability to interact with model membranes. In U937 human leukemia cells, a second system in which PMA and bryostatin 1 have divergent effects, viz. PMA but not bryostatin 1 inhibits proliferation and induces attachment, all the compounds acted like PMA for proliferation, but several induced a reduced level or a biphasic dose-response curve for attachment. We conclude that active phorbol esters are not all equivalent. Depending on the system, some might partially resemble bryostatin 1 in their behavior; this encourages the concept that bryostatin-like behavior may be obtained from other structural templates.
ChemBioChem 05/2011; 12(8):1242-51. · 3.94 Impact Factor
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ABSTRACT: Switching on kinases: Synthetic caged DAG-lactones have been developed and showed decreases of two orders of magnitude, relative to the corresponding parent compounds, in their binding affinities towards PKC. The caged compounds had no effect on the translocation of PKC until after photoactivation. This approach is a potentially powerful tool for probing the PKC signaling cascade.
ChemBioChem 03/2011; 12(4):535-9. · 3.94 Impact Factor
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ABSTRACT: The transient receptor potential vanilloid subtype 1 (TRPV1) is a non-selective cation channel composed of four monomers with six transmembrane helices (TM1-TM6). TRPV1 is found in the central and peripheral nervous system, and it is an important therapeutic target for pain relief. We describe here the construction of a tetrameric homology model of rat TRPV1 (rTRPV1). We experimentally evaluated by mutational analysis the contribution of residues of rTRPV1 contributing to ligand binding by the prototypical TRPV1 agonists, capsaicin and resiniferatoxin (RTX). We then performed docking analysis using our homology model. The docking results with capsaicin and RTX showed that our homology model was reliable, affording good agreement with our mutation data. Additionally, the binding mode of a simplified RTX (sRTX) ligand as predicted by the modeling agreed well with those of capsaicin and RTX, accounting for the high binding affinity of the sRTX ligand for TRPV1. Through the homology modeling, docking and mutational studies, we obtained important insights into the ligand-receptor interactions at the molecular level which should prove of value in the design of novel TRPV1 ligands.
Journal of Computer-Aided Molecular Design 03/2011; 25(4):317-27. · 3.39 Impact Factor
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Noemi Kedei,
Andrea Telek,
Alexandra Czap,
Emanuel S Lubart,
Gabriella Czifra,
Dazhi Yang,
Jinqiu Chen,
Tyler Morrison,
Paul K Goldsmith,
Langston Lim,
Poonam Mannan,
Susan H Garfield,
Matthew B Kraft,
Wei Li,
Gary E Keck, Peter M Blumberg
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ABSTRACT: Bryostatin 1 has attracted considerable attention both as a cancer chemotherapeutic agent and for its unique activity. Although it functions, like phorbol esters, as a potent protein kinase C (PKC) activator, it paradoxically antagonizes many phorbol ester responses in cells. Because of its complex structure, little is known of its structure-function relations. Merle 23 is a synthetic derivative, differing from bryostatin 1 at only four positions. However, in U-937 human leukemia cells, Merle 23 behaves like a phorbol ester and not like bryostatin 1. Here, we characterize the behavior of Merle 23 in the human prostate cancer cell line LNCaP. In this system, bryostatin 1 and phorbol ester have contrasting activities, with the phorbol ester but not bryostatin 1 blocking cell proliferation or tumor necrosis factor alpha secretion, among other responses. We show that Merle 23 displays a highly complex pattern of activity in this system. Depending on the specific biological response or mechanistic change, it was bryostatin-like, phorbol ester-like, intermediate in its behavior, or more effective than either. The pattern of response, moreover, varied depending on the conditions. We conclude that the newly emerging bryostatin derivatives such as Merle 23 provide powerful tools to dissect subsets of bryostatin mechanism and response.
Biochemical pharmacology 03/2011; 81(11):1296-308. · 4.25 Impact Factor
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ABSTRACT: Bryostatin 2 (1a) has been converted to bryostatin 1 (1e) and bryostatin 12 (1i) by a selective protection and deprotection involving the C-26 hydroxyl group. The new bryostatins 1g,1k, and 1m were also prepared starting from bryostatin 2. The C-7 substituents of natural bryostatins 4 and 5 were revised from isovalerate → pivalate employing comparative 1H and 13C NMR studies of the semi-synthetic bryostatins 1k and 1m and the natural products. Key words: bryostatin 2 → 1, selective conversion, bryostatins 4 and 5, pivalates.
Canadian Journal of Chemistry 02/2011; 69(5):856-860. · 1.24 Impact Factor
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ABSTRACT: A series of 5'-halogenated resiniferatoxin analogs have been investigated in order to examine the effect of halogenation in the A-region on their binding and the functional pattern of agonism/antagonism for rat TRPV1 heterologously expressed in Chinese hamster ovary cells. Halogenation at the 5-position in the A-region of RTX and of 4-amino RTX shifted the agonism of parent compounds toward antagonism. The extent of antagonism was greater as the size of the halogen increased (I > Br > Cl > F) while the binding affinities were similar, as previously observed for our potent agonists. In this series, 5-bromo-4-amino RTX (39) showed very potent antagonism with K(i) (ant) = 2.81 nM, which was thus 4.5-fold more potent than 5'-iodo RTX, previously reported as a potent TRPV1 antagonist. Molecular modeling analyses with selected agonists and the corresponding halogenated antagonists revealed a striking conformational difference. The 3-methoxy of the A-region in the agonists remained free to interact with the receptor whereas in the case of the antagonists, the compounds assumed a bent conformation, permitting the 3-methoxy to instead form an internal hydrogen bond with the C4-hydroxyl of the diterpene.
Bioorganic & medicinal chemistry letters 01/2011; 21(1):299-302. · 2.65 Impact Factor
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ABSTRACT: Protein kinase C (PKC) is a critical cell signaling pathway involved in many disorders such as cancer and Alzheimer-type dementia. To date, evaluation of PKC ligand binding affinity has been performed by competitive studies against radiolabeled probes that are problematic for high-throughput screening. In the present study, we have developed a fluorescent-based binding assay system for identifying ligands that target the PKC ligand binding domain (C1 domain). An environmentally sensitive fluorescent dye (solvatochromic fluorophore), which has been used in multiple applications to assess protein-binding interactions, was inserted in proximity to the binding pocket of a novel PKCδ C1b domain. These resultant fluorescent-labeled δC1b domain analogues underwent a significant change in fluorescent intensity upon ligand binding, and we further demonstrate that the fluorescent δC1b domain analogues can be used to evaluate ligand binding affinity.
Bioconjugate Chemistry 01/2011; 22(1):82-7. · 4.93 Impact Factor
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Or Raifman,
Sofiya Kolusheva,
Said El Kazzouli,
Dina M Sigano,
Noemi Kedei,
Nancy E Lewin,
Ruben Lopez-Nicolas,
Ana Ortiz-Espin,
Juan C Gomez-Fernandez, Peter M Blumberg,
Victor E Marquez,
Senena Corbalan-Garcia,
Raz Jelinek
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ABSTRACT: Synthetic diacylglycerol-lactones (DAG-lactones) are effective modulators of critical cellular signaling pathways, downstream of the lipophilic second messenger diacylglycerol, that activate a host of protein kinase C (PKC) isozymes and other nonkinase proteins that share similar C1 membrane-targeting domains with PKC. A fundamental determinant of the biological activity of these amphiphilic molecules is the nature of their interactions with cellular membranes. This study examines the biological properties of charged DAG-lactones exhibiting different alkyl groups attached to the heterocyclic nitrogen of an α-pyridylalkylidene chain, and particularly the relationship between membrane interactions of the substituted DAG-lactones and their respective biological activities. Our results suggest that bilayer interface localization of the N-alkyl chain in the R(2) position of the DAG-lactones inhibits translocation of PKC isoenzymes onto the cellular membrane. However, the orientation of a branched alkyl chain at the bilayer surface facilitates PKC binding and translocation. This investigation emphasizes that bilayer localization of the aromatic side residues of positively charged DAG-lactone derivatives play a central role in determining biological activity, and that this factor contributes to the diversity of biological actions of these synthetic biomimetic ligands.
ChemBioChem 09/2010; 11(14):2003-9. · 3.94 Impact Factor
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Or Raifman,
Sofiya Kolusheva,
Said El Kazzouli,
Dina M Sigano,
Noemi Kedei,
Nancy E Lewin,
Ruben Lopez-Nicolas,
Ana Ortiz-Espin,
Juan C Gomez-Fernandez, Peter M Blumberg,
Victor E Marquez,
Senena Corbalan-Garcia,
Raz Jelinek
ChemBioChem 09/2010; 11(14):1926. · 3.94 Impact Factor
