Publications

• A novel cytosolic calcium-independent phospholipase A2 contains eight ankyrin motifs.

  Tang J., Kriz R.W., Wolfman N., Shaffer M., Seehra J., Jones S.S.

  We report the purification, molecular cloning, and expression of a novel cytosolic calcium-independent phospholipase A2 (iPLA2) from Chinese hamster ovary cells, which lacks extended homology to other phospholipases. iPLA2 is an 85-kDa protein that exists as a multimeric complex of 270-350 kDa wit ... >> More

  We report the purification, molecular cloning, and expression of a novel cytosolic calcium-independent phospholipase A2 (iPLA2) from Chinese hamster ovary cells, which lacks extended homology to other phospholipases. iPLA2 is an 85-kDa protein that exists as a multimeric complex of 270-350 kDa with a specific activity of 1 micromol/min/mg. The full-length cDNA clone encodes a 752-amino acid cytoplasmic protein with one lipase motif (GXS465XG) and eight ankyrin repeats. Expression of the cDNA in mammalian cells generates an active 85-kDa protein. Mutagenesis studies show that Ser465 and the ankyrin repeats are required for activity. We demonstrate that iPLA2 selectively hydrolyzes the sn-2 over sn-1 fatty acid by 5-fold for 1,2-dipalmitoyl phosphatidylcholine in a mixed micelle. Moreover, we found the fatty acid preference at the sn-2 position to be highly dependent upon substrate presentation. However, iPLA2 does have a marked preference for 1,2-dipalmitoyl phosphatidic acid presented in a vesicle, generating the lipid second messenger lysophosphatidic acid. Finally the enzyme is able to hydrolyze the acetyl moiety at the sn-2 position of platelet-activating factor. << Less

  J. Biol. Chem. 272:8567-8575(1997) [PubMed] [EuropePMC]

  This publication is cited by 8 other entries.

• The genomic organization, complete mRNA sequence, cloning, and expression of a novel human intracellular membrane-associated calcium-independent phospholipase A(2).

  Mancuso D.J., Jenkins C.M., Gross R.W.

  During the sequencing of the long arm of chromosome 7 in the Human Genome Project, a predicted protein product of 40 kDa was identified, which contained two approximately 10-amino acid segments homologous to the ATP and lipase consensus sequences present in the founding members of a family of calc ... >> More

  During the sequencing of the long arm of chromosome 7 in the Human Genome Project, a predicted protein product of 40 kDa was identified, which contained two approximately 10-amino acid segments homologous to the ATP and lipase consensus sequences present in the founding members of a family of calcium-independent phospholipases A(2). Detailed inspection of the identified sequence (residues 79, 671-109,912 GenBank accession no. AC005058) demonstrated that it represented only a partial sequence of a larger undefined polypeptide product. Accordingly, we identified the complete genomic organization of this putative phospholipase A(2) through analyses of previously published expressed sequence tags, PCR of human heart cDNA, and 5'-rapid amplification of cDNA ends. Polymerase chain reaction and Northern blotting demonstrated a 3.4-kilobase message, which encoded a polypeptide with a maximum calculated molecular weight of 88476.9. This 3.4-kilobase message was present in multiple human parenchymal tissues including heart, skeletal muscle, placenta, brain, liver, and pancreas. Cloning and expression of the protein encoded by this message in Sf9 cells resulted in the production of two proteins of apparent molecular masses of 77 and 63 kDa as assessed by Western analyses utilizing immunoaffinity-purified antibody. Membranes from Sf9 cells expressing recombinant protein released fatty acid from sn-2-radiolabeled phosphatidylcholine and plasmenylcholine up to 10-fold more rapidly than controls. The initial rate of fatty acid release from the membrane fraction was 0. 3 nmol/mg.min. The recombinant protein was entirely calcium-independent, had a pH optimum of 8.0, was inhibited by (E)-6-(bromomethylene)-3-(1-naphthalenyl)-2H-tetrahydropyran-2-one (IC(50) = 3 microM), and was predominantly present in the membrane-associated fraction. Collectively, these results describe the genomic organization, complete mRNA sequence, and sn-2-lipase activity of a novel intracellular calcium-independent membrane-associated phospholipase A(2). << Less

  J. Biol. Chem. 275:9937-9945(2000) [PubMed] [EuropePMC]

  This publication is cited by 3 other entries.

• Cellular arachidonate-releasing function of novel classes of secretory phospholipase A2s (groups III and XII).

  Murakami M., Masuda S., Shimbara S., Bezzine S., Lazdunski M., Lambeau G., Gelb M.H., Matsukura S., Kokubu F., Adachi M., Kudo I.

  Here we report cellular arachidonate (AA) release and prostaglandin (PG) production by novel classes of secretory phospholipase A(2)s (sPLA(2)s), groups III and XII. Human group III sPLA(2) promoted spontaneous AA release, which was augmented by interleukin-1, in HEK293 transfectants. The central ... >> More

  Here we report cellular arachidonate (AA) release and prostaglandin (PG) production by novel classes of secretory phospholipase A(2)s (sPLA(2)s), groups III and XII. Human group III sPLA(2) promoted spontaneous AA release, which was augmented by interleukin-1, in HEK293 transfectants. The central sPLA(2) domain alone was sufficient for its in vitro enzymatic activity and for cellular AA release at the plasma membrane, whereas either the unique N- or C-terminal domain was required for heparanoid-dependent action on cells to augment AA release, cyclooxygenase-2 induction, and PG production. Group III sPLA(2) was constitutively expressed in two human cell lines, in which other sPLA(2)s exhibited different stimulus inducibility. Human group XII sPLA(2) had a weak enzymatic activity in vitro and minimally affects cellular AA release and PG production. Cells transfected with group XII sPLA(2) exhibited abnormal morphology, suggesting a unique functional aspect of this enzyme. Based on the present results as well as our current analyses on the group I/II/V/X sPLA(2)s, general properties of cellular actions of a full set of mammalian sPLA(2)s in regulating AA metabolism are discussed. << Less

  J. Biol. Chem. 278:10657-10667(2003) [PubMed] [EuropePMC]

  This publication is cited by 3 other entries.

• Cloning of a gene for a novel epithelium-specific cytosolic phospholipase A2, cPLA2delta, induced in psoriatic skin.

  Chiba H., Michibata H., Wakimoto K., Seishima M., Kawasaki S., Okubo K., Mitsui H., Torii H., Imai Y.

  Psoriasis is a common skin disease characterized by hyperplastic regenerative epidermal growth and infiltration of immunocytes. The etiology of psoriasis is unknown, although several genetic and cellular factors have been elucidated. To find new psoriasis-related genes, we have cloned cDNAs that a ... >> More

  Psoriasis is a common skin disease characterized by hyperplastic regenerative epidermal growth and infiltration of immunocytes. The etiology of psoriasis is unknown, although several genetic and cellular factors have been elucidated. To find new psoriasis-related genes, we have cloned cDNAs that are differentially expressed between normal and psoriatic skins. Among these clones, we have identified a new gene that codes for a new member of the type IV cytosolic phospholipase A(2) (cPLA(2)) family. We refer to this gene as cPLA(2)delta. It encodes a polypeptide of 818 amino acids that has significant homology with known cPLA(2) proteins in the C2 and catalytic domains. The cPLA(2)delta gene was mapped to the 15q13-14 chromosomal locus, near to the locus of the cPLA(2)beta gene, from which it is separated by a physical distance of about 220 kb. To identify the phospholipase A(2) activity of cPLA(2)delta, we transfected COS-7 cells with His-tagged cPLA(2)delta. The cell lysate from these cells had calcium-dependent phospholipase A(2) activity. Northern blot analysis revealed that a cPLA(2)delta transcript of about 4 kb is expressed in stratified squamous epithelia, such as those in skin and cervix, but not in other tissues. In situ hybridization and immunohistochemistry revealed that cPLA(2)delta is expressed strongly in the upper spinous layer of the psoriatic epidermis, expressed weakly and discontinuously in atopic dermatitis and mycosis fungoides, and not detected in the epidermis of normal skin; cPLA(2)alpha is not detected in either normal or psoriatic skin. These results suggest that cPLA(2)delta exhibits a unique distribution pattern compared with that of known cPLA(2) subtypes, and it may play a critical role in inflammation in psoriatic lesions. << Less

  J. Biol. Chem. 279:12890-12897(2004) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.

• Identification and functional characterization of adipose-specific phospholipase A2 (AdPLA).

  Duncan R.E., Sarkadi-Nagy E., Jaworski K., Ahmadian M., Sul H.S.

  Phospholipases A(2) (PLA(2)s) catalyze hydrolysis of fatty acids from the sn-2 position of phospholipids. Here we report the identification and characterization of a membrane-associated intracellular calcium-dependent, adipose-specific PLA(2) that we named AdPLA (adipose-specific phospholipase A(2 ... >> More

  Phospholipases A(2) (PLA(2)s) catalyze hydrolysis of fatty acids from the sn-2 position of phospholipids. Here we report the identification and characterization of a membrane-associated intracellular calcium-dependent, adipose-specific PLA(2) that we named AdPLA (adipose-specific phospholipase A(2)). We found that AdPLA was highly expressed specifically in white adipose tissue and was induced during preadipocyte differentiation into adipocytes. Clearance of AdPLA by immunoprecipitation significantly decreased PLA activity in white adipose tissue lysates but had no effect on liver lysates, where expression was hardly detectable. In characterizing AdPLA, we employed radiochemical assays with TLC analysis of the enzyme activity of lysates from COS-7 cells overexpressing AdPLA. For kinetic studies, we produced purified recombinant AdPLA for use in a lipoxidase-coupled spectrophotometric assay. AdPLA generated free fatty acid and lysophospholipid from phosphatidylcholine with a preference for hydrolysis at the sn-2 position. Although we found low but detectable lysophospholipase activity, AdPLA showed no significant activity against a variety of other lipid substrates. Calcium was found to activate AdPLA but was not essential for activity. Studies with known phospholipase inhibitors, including bromoenolactone, methyl arachidonyl fluorophosphate, AACOCF(3), 7,7-dimethyl-5,8-eicosadienoic acid, and thioetheramide, supported that AdPLA is a phospholipase. Mutational studies showed that His-23 and Cys-113 are critical for activity of AdPLA and suggested that AdPLA is likely a His/Cys PLA(2). Overall, although AdPLA is similar to other histidine phospholipases in pH and calcium dependence, AdPLA showed different characteristics in many regards, including predicted catalytic mechanism. AdPLA may therefore represent the first member of a new group of PLA(2)s, group XVI. << Less

  J. Biol. Chem. 283:25428-25436(2008) [PubMed] [EuropePMC]

  This publication is cited by 3 other entries.

• Messenger RNAs expressed in intestine of adult but not baby rabbits. Isolation of cognate cDNAs and characterization of a novel brush border protein with esterase and phospholipase activity.

  Boll W., Schmid-Chanda T., Semenza G., Mantei N.

  Using a subtractive hybridization method, we have cloned cDNAs corresponding to 10 different mRNAs which share the property of being expressed in the intestine of adult but not baby rabbits. Four could be identified as coding for previously known gene products (sucrase-isomaltase, a glutathione S- ... >> More

  Using a subtractive hybridization method, we have cloned cDNAs corresponding to 10 different mRNAs which share the property of being expressed in the intestine of adult but not baby rabbits. Four could be identified as coding for previously known gene products (sucrase-isomaltase, a glutathione S-transferase, a cytochrome P450, and a long form of ferritin mRNA), while six code for previously unknown proteins. One clone, AdRab-B, codes for a protein of 1458 amino acids, including (i) a putative signal sequence at the NH2 terminus, (ii) four internal repeats, 308-346 amino acids in length, (iii) a hydrophobic stretch near the COOH terminus, which represents a potential membrane anchor, and (iv) a short hydrophilic stretch at the very COOH terminus. The corresponding protein was studied with the aid of antibodies prepared against polypeptides expressed from segments of the cDNA in Escherichia coli. The protein was shown to be proteolytically processed in the intestine (but not when expressed in COS cells) and to be targeted to the brush border membrane of the enterocytes. Finally, the protein was found to have esterase and phospholipase A/lysophospholipase activity. << Less

  J. Biol. Chem. 268:12901-12911(1993) [PubMed] [EuropePMC]

  This publication is cited by 8 other entries.

• Negative charge at amino acid 149 is the molecular determinant for substrate specificity of lecithin: cholesterol acyltransferase for phosphatidylcholine containing 20-carbon sn-2 fatty acyl chains.

  Zhao Y., Wang J., Gebre A.K., Chisholm J.W., Parks J.S.

  We previously described a point mutation in human LCAT (E to A at residue 149; hE149A) that demonstrated greater activity with phosphatidylcholine (PC) substrate containing 20:4 in the sn-2 position compared with the wild-type enzyme [hLCAT; Wang et al. (1997) J. Biol. Chem. 272, 280-286], resulti ... >> More

  We previously described a point mutation in human LCAT (E to A at residue 149; hE149A) that demonstrated greater activity with phosphatidylcholine (PC) substrate containing 20:4 in the sn-2 position compared with the wild-type enzyme [hLCAT; Wang et al. (1997) J. Biol. Chem. 272, 280-286], resulting in a human enzyme with the substrate specificity similar to that of rat LCAT. The purpose of the present study was to explore the molecular basis for the role of amino acid 149 in determining fatty acyl substrate specificity. In the first experiment, the reverse mutation in rat LCAT (rA149E) converted substrate specificity of rat LCAT toward that of the human enzyme, demonstrating that the mutation was context independent and reversible. In the second experiment, we found that hE149A compared with hLCAT demonstrated higher activity with PC species containing 20-carbon, but not 18-carbon, sn-2 fatty acyl chains. The increased activity of hE149A was due to an increase in apparent V(max) but not to apparent K(m) or LCAT binding to the PC surface. Substitution of different amino acids in the 149 position of hLCAT showed that activation of the enzyme with sn-2 20:4 containing PC substrate was only observed when the negative charge at residue 149 was removed. We conclude that the negative charge at amino acid 149 of LCAT is a critical determinant for the specificity of the enzyme for PC containing 18- vs 20-carbon sn-2 fatty acyl chains. << Less

  Biochemistry 42:13941-13949(2003) [PubMed] [EuropePMC]

  This publication is cited by 12 other entries.

• Cloning and characterization of novel mouse and human secretory phospholipase A2s.

  Ishizaki J., Suzuki N., Higashino K., Yokota Y., Ono T., Kawamoto K., Fujii N., Arita H., Hanasaki K.

  Mammalian secretory phospholipase A(2)s (sPLA(2)s) are classified into several groups according to molecular structure and the localization of intramolecular disulfide bridges. Among them, group IIA sPLA(2) has been thought to be one of the key enzymes in the pathogenesis of inflammatory diseases ... >> More

  Mammalian secretory phospholipase A(2)s (sPLA(2)s) are classified into several groups according to molecular structure and the localization of intramolecular disulfide bridges. Among them, group IIA sPLA(2) has been thought to be one of the key enzymes in the pathogenesis of inflammatory diseases owing to its augmented expression under various inflammatory conditions. However, in a number of inbred mouse strains, the group IIA sPLA(2) gene is naturally disrupted by a frameshift mutation. Here, we report the cloning of a cDNA encoding a novel sPLA(2) expressed in the spleen of group IIA sPLA(2)-deficient mouse. We also cloned its human homolog and mapped its gene location on chromosome 1p36.12 near the loci of group IIA and V sPLA(2) genes. The human mature sPLA(2) protein consists of 125 amino acids (M(r) = 14,500) preceded by a 20-residue prepeptide and is most similar to group IIA sPLA(2) with respect to the number and positions of cysteine residues as well as overall identity (48%). Based on these structural properties, the novel sPLA(2) should be categorized into group II, called group IID to follow the already identified IIA to IIC sPLA(2)s. When the cDNA was expressed in COS-7 cells, PLA(2) activity preferentially accumulated in the culture medium. It is maximally active at neutral to alkaline pH and with 2 mM Ca(2+). In assays with individual substrates, L-alpha-1-palmitoyl-2-linoleoyl phosphatidylethanolamine was more efficiently hydrolyzed than the other phospholipids examined. An RNA blot hybridized with the cDNA exhibited two transcripts (2.0 and 1.0 kb) in human spleen, thymus, and colon. The expression of a novel sPLA(2) mRNA was elevated in the thymus after treatment with endotoxin in rats as well as in group IIA sPLA(2)-deficient mice, suggesting its functional role in the progression of the inflammatory process. << Less

  J. Biol. Chem. 274:24973-24979(1999) [PubMed] [EuropePMC]

  This publication is cited by 8 other entries.

• Structure/Function relationships of adipose phospholipase A2 containing a cys-his-his catalytic triad.

  Pang X.Y., Cao J., Addington L., Lovell S., Battaile K.P., Zhang N., Rao J.L., Dennis E.A., Moise A.R.

  Adipose phospholipase A(2) (AdPLA or Group XVI PLA(2)) plays an important role in the onset of obesity by suppressing adipose tissue lipolysis. As a consequence, AdPLA-deficient mice are resistant to obesity induced by a high fat diet or leptin deficiency. It has been proposed that AdPLA mediates ... >> More

  Adipose phospholipase A(2) (AdPLA or Group XVI PLA(2)) plays an important role in the onset of obesity by suppressing adipose tissue lipolysis. As a consequence, AdPLA-deficient mice are resistant to obesity induced by a high fat diet or leptin deficiency. It has been proposed that AdPLA mediates its antilipolytic effects by catalyzing the release of arachidonic acid. Based on sequence homology, AdPLA is part of a small family of acyltransferases and phospholipases related to lecithin:retinol acyltransferase (LRAT). To better understand the enzymatic mechanism of AdPLA and LRAT-related proteins, we solved the crystal structure of AdPLA. Our model indicates that AdPLA bears structural similarity to proteins from the NlpC/P60 family of cysteine proteases, having its secondary structure elements configured in a circular permutation of the classic papain fold. Using both structural and biochemical evidence, we demonstrate that the enzymatic activity of AdPLA is mediated by a distinctive Cys-His-His catalytic triad and that the C-terminal transmembrane domain of AdPLA is required for the interfacial catalysis. Analysis of the enzymatic activity of AdPLA toward synthetic and natural substrates indicates that AdPLA displays PLA(1) in addition to PLA(2) activity. Thus, our results provide insight into the enzymatic mechanism and biochemical properties of AdPLA and LRAT-related proteins and lead us to propose an alternate mechanism for AdPLA in promoting adipose tissue lipolysis that is not contingent on the release of arachidonic acid and that is compatible with its combined PLA(1)/A(2) activity. << Less

  J. Biol. Chem. 287:35260-35274(2012) [PubMed] [EuropePMC]

  This publication is cited by 9 other entries.