Cellular & Molecular Biology Letters
International Scientific Journal
Established 1996
Volume 12 (2007) No. 4
| DOI: 10.2478/s11658-007-0015-0 Volume 12 (2007) pp 473 - 481 | |
| Title | THE NEUROPROTECTIVE EFFECT OF Withania somnifera ROOT EXTRACT IN MPTP-INTOXICATED MICE: AN ANALYSIS OF BEHAVIORAL AND BIOCHEMICAL VARIBLES |
| Authors | Srinivasagam Raja Sankar1*, Thamilarasan Manivasagam2, Arumugam Krishnamurti1 and Manickam Ramanathan3 |
| Abstract | We studied the influence of Withania somnifera (Ws) root extract (100 mg/kg body weight) on parkinsonism induced by 1-methyl 4-phenyl 1,2,3,6-tetrahydropyridine (MPTP; i.p, 20 mg/kg body weight for 4 days), via the analysis of behavioral features and the oxidant-antioxidant imbalance in the midbrain of mice. A significant alteration in behavior, increased levels of thiobarbituric acid reactive substance (TBARS), and increased activities of superoxide dismutase (SOD) and catalase (CAT) were noticed in this region of brain in MPTP-treated mice. Oral treatment with the root extract resulted in a significant improvement in the mice’s behavoiur and antioxidant status, along with a significant reduction in the level of lipid peroxidation. The results indicated that at least part of the chronic stress-induced pathology may be due to oxidative stress, which is mitigated by Ws. Further studies are needed to assess the precise mechanism to support the clinical use of the plant as an antiparkinsonic drug. |
| Keywords | MPTP, Withania somnifera, TBARS, Antioxidants, Behaviour, Midbrain |
| Adress and Contact Informations | 1Department of Anatomy, Faculty of Medicine, Annamalai University,
Annamalainagar, 608 002, India, 2Department of Biochemistry and Biotechnology, Faculty of Science, Annamalai University, Annamalainagar, 608 002, India, 3Department of Surgery, Faculty of Medicine, Annamalai University, Annamalainagar, 608 002, India * Author for correspondence; e-mail: anatomysrs@yahoo.com, tel: + 91-4144-239645, fax : + 91-4144-238145 |
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| DOI: 10.2478/s11658-007-0016-z Volume 12 (2007) pp 482 - 492 | |
| Title | MOLECULAR CLONING AND ANALYSIS OF THE HUMAN PCAN1 (GDEP) PROMOTER |
| Authors | Wenwen Liu, Weiwen Chen, Pengju Zhang, Chunxiao Yu, Feng Kong, Jingti Deng, Jianye Zhang* and Anli Jiang* |
| Abstract | Human PCAN1 (prostate cancer gene 1) is a prostate-specific gene that is highly expressed in prostate epithelial tissue, and frequently mutated in prostate tumors. To better understand the regulation of the PCAN1 gene, a 2.6-kb fragment of its 5’ flanking region was obtained by PCR. Its promoter activity was examined via the dual-luciferase reporter assay after it had been cloned into a pGL3-basic vector generating pGL3-p2.6kb and transfected into LNCaP cells. pGL3-basic and pGL3-control were respectively used as the negative and positive controls. Sequence analysis with the MatInspector database showed that some possible binding sites for the transcriptional factors, NKX3.1, P53, SP1, cEBP and the PPAR/RXR heterodimers may locate on a 2.6-kb region upstream of the PCAN1 gene. To examine the relevant regulation of PCAN1, pGL3-p2.6kb was transfected into the prostate cancer cell line LNCaP, which was treated with R1881 (10-7~10-9 mol/l), 17ß-estradiol (17ß-E2, 10-7~10-9 mol/l), all-trans-retinoic acid (all-trans-RA, 10-5~10-7 mol/l) or 9-cis-retinoic acid (9-cis-RA, 10-5~10-7 mol/l), and eukaryotic expression plasmids of NKX3.1, p53, Sp1, Pten, PPARγ or cEBPα were cotransfected with pGL3-p2.6kb into LNCaP cells. pRL-TK, a Renilla luciferase reporter vector, was cotransfected into all the transfection lines as an internal control. The activities of pGL3-p2.6kb (PCAN1 promoter) were analyzed via the dualluciferase reporter assay 48 h after transfection. The results showed that 9-cis- RA enhanced the PCAN1 promoter activity in a dose-dependent manner, while R1881, 17ß-E2 and all-trans-RA had no significant effect on PCAN1 promoter activities. Cotransfection with pGL3-p2.6kb and the expression plasmids of NKX3.1, p53, Sp1 or Pten respectively resulted in 1.66-, 2.48-, 2.00- and 1.72-fold 2.6 kb PCAN1 promoter activity increases relative to the controls, which were cotransfected with pcDNA3.1(+), while cotransfection of PPARγ and cEBPα yielded no significant effect on PCAN1 promoter activities. These results could be applied for further study of the function and transcription regulation of the PCAN1 gene in prostate development and carcinogenesis. |
| Keywords | PCAN1, Promoter, Transfection, Luciferase reporter assay, Prostate cancer cell |
| Adress and Contact Informations | Institute of Biochemistry and Molecular Biology, School of Medicine, Shandong
University, Jinan 250012, China * Authors for correspondence; e-mail: Jianganli@sdu.edu.cn, zhjy@sdu.edu.cn, tel: +86-531-88382092-4 |
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| DOI: 10.2478/s11658-007-0019-9 Volume 12 (2007) pp 493 - 508 | |
| Title | STILBENE DERIVATIVES INHIBIT THE ACTIVITY OF THE INNER MITOCHONDRIAL MEMBRANE CHLORIDE CHANNELS |
| Authors | Izabela Koszela-Piotrowska1, Katarzyna Choma1,2, Piotr Bednarczyk1,2, Krzysztof Dołowy2, Adam Szewczyk1, Wolfram S. Kunz3, Lubica Malekova4, Viera Kominkova4 and Karol Ondrias4 |
| Abstract | Ion channels selective for chloride ions are present in all biological membranes, where they regulate the cell volume or membrane potential. Various chloride channels from mitochondrial membranes have been described in recent years. The aim of our study was to characterize the effect of stilbene derivatives on single-chloride channel activity in the inner mitochondrial membrane. The measurements were performed after the reconstitution into a planar lipid bilayer of the inner mitochondrial membranes from rat skeletal muscle (SMM), rat brain (BM) and heart (HM) mitochondria. After incorporation in a symmetric 450/450 mM KCl solution (cis/trans), the chloride channels were recorded with a mean conductance of 155 ± 5 pS (rat skeletal muscle) and 120 ± 16 pS (rat brain). The conductances of the chloride channels from the rat heart mitochondria in 250/50 mM KCl (cis/trans) gradient solutions were within the 70-130 pS range. The chloride channels were inhibited by these two stilbene derivatives: 4,4’-diisothiocyanostilbene-2,2’-disulfonic acid (DIDS) and 4-acetamido-4’- isothiocyanostilbene-2,2’-disulfonic acid (SITS). The skeletal muscle mitochondrial chloride channel was blocked after the addition of 1 mM DIDS or SITS, whereas the brain mitochondrial channel was blocked by 300 µM DIDS or SITS. The chloride channel from the rat heart mitochondria was inhibited by 50-100 µM DIDS. The inhibitory effect of DIDS was irreversible. Our results confirm the presence of chloride channels sensitive to stilbene derivatives in the inner mitochondrial membrane from rat skeletal muscle, brain and heart cells. |
| Keywords | Mitochondria, Chloride channel, Stilbene derivatives, Black lipid membrane |
| Adress and Contact Informations | 1Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental
Biology, Pasteura 3, 02-093 Warsaw, Poland, 2Department of Biophysics, Agricultural University SGGW, Nowoursynowska 159, 02-776 Warsaw, Poland, 3Department of Epileptology, University Bonn Medical Center, Sigmund-Freud- Str. 25, D-53105 Bonn, Germany, 4Laboratory of Intracellular Ion Channels, Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Vlarska 5, 83334 Bratislava, Slovak Republic * Author for correspondence: e-mail: i.piotrowska@ne ncki.gov.pl, tel. +4822 5892 343 |
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| DOI: 10.2478/s11658-007-0020-3 Volume 12 (2007) pp 509 - 522 | |
| Title | PROCASPASE-9 IS ATTACHED TO THE MITOCHONDRIAL OUTER MEMBRANE IN THE EARLY STAGES OF APOPTOSIS |
| Authors | Irina Milisav* and Dusan Suput |
| Abstract | Procaspase-9 is the zymogen form of one of the apoptosis initiators, caspase-9. Its cellular location may differ depending on the cell type; it is found throughout the cytosol, although some of it may be associated with the mitochondria. Procaspase-9 relocates from the cytosol to the mitochondria shortly after the triggering of apoptosis in rat hepatocytes. We investigated whether the mitochondrial protein import machineries import procaspase-9. The combined results of protein import analyses, mitochondrial fractionation and protease treatments of intact and swollen mitochondria imply that procaspase-9 attaches to the outer surface of the mitochondrial outer membrane. |
| Keywords | Caspase-9, Procaspase-9, Mitochondria, Apoptosis, Protein import, Rotenone, Localization |
| Adress and Contact Informations | University of Ljubljana, Medical Faculty, Institute of Pathophysiology, Zaloška 4,
SI-1000 Ljubljana, Slovenia * Author for correspondence; e-mail: irina.milisav@mf.uni-lj.si, tel: +386-1-543-7089, fax: +386-1-543-7021 |
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| DOI: 10.2478/s11658-007-0023-0 Volume 12 (2007) pp 523 - 535 | |
| Title | THE IDENTIFICATION OF QTLs ASSOCIATED WITH THE in vitro RESPONSE OF RYE (Secale cereale L.) |
| Authors | Hanna Bolibok, Anna Gruszczyńska, Aneta Hromadajudycka and Monika Rakoczy-Trojanowska* |
| Abstract | This study was conducted in order to identify quantitative trait loci (QTLs) for the in vitro culture response of winter rye (Secale cereale L.) immature embryos and immature inflorescences. A genetic linkage map comprising 67 SSRs, 9 ISSRs, 13 SAMPLs, 7 RAPDs, 2 SCARs and one EST marker was created based on the analyses of 102 recombinant inbred lines from the cross between lines L318 (which has a good response in tissue cultures) and L9 (which is unable to regenerate plants from somatic tissues and anthers). The map spans 979.2 cM, and the average distance between markers is 9.9 cM. Two characteristics were evaluated: callus induction (CI) and somatic embryogenesis ability (SE). They were expressed as the percentage of immature embryos/inflorescences producing callus (designated ECI/ICI) and the percentage of explants producing somatic embryos (ESE/ISE). All the analysed traits showed continuous variation in the mapping population but a non-normal frequency distribution. We identified nine putative QTLs controlling the tissue culture response of rye, explaining up to 41.6% of the total phenotypic variation: two QTLs for ECI – eci-1, eci-2; 4 for ESE – ece-1, ese-2, ese-3, ese-4; 2 for ICI – ici-1, ici2; and 1 for ISE – ise-1. They were detected on chromosomes 1R, 4R, 5R, 6R and 7R. |
| Keywords | Rye, Secale cereale L., Somatic embryogenesis, Tissue culture, Immature embryos, Immature inflorescences, Molecular marker, QTL, Genetic mapping |
| Adress and Contact Informations | Department of Plant Genetics, Breeding and Biotechnology, Warsaw
Agricultural University, Nowoursynowska 159, 02-776 Warszawa, Poland * Author for correspondence: e-mail: Monika_Rakoczy_Trojanowska@sggw.pl |
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| DOI: 10.2478/s11658-007-0025-y Volume 12 (2007) pp 536 - 544 | |
| Title | MICROGLIAL EXPRESSION OF PEPTIDYLARGININE DEIMINASE 2 IN THE PRENATAL RAT BRAIN |
| Authors | Hiroaki Asaga1* and Akihito Ishigami2 |
| Abstract | Peptidylarginine deiminases (PADs) are Ca2+-dependant posttranslational modification enzymes that catalyze the citrullination of protein arginyl residues. PAD type 2 (PAD2) is thought to be involved in some processes of neurodegeneration and myelination in the central nervous system. In this study, we found PAD2-positive cells in rat cerebra in 19- to 21-day old embryos, i.e. at a developmental stage well before myelination begins. Most of the cells were microglial marker-positive cells found mainly in the prospective medulla, and others were microglial marker-negative cells found mainly in the prospective dentate gyrus of the hippocampus. The former seemed to be in an activated state as judged by morphological criteria. The specificity of the enzyme activity, immunoblotting and reverse transcriptase-polymerase chain reaction analyses revealed that these cells expressed PAD2 and not PAD1, PAD3 or PAD4. Our data is indicative of microglial expression of PAD2 in the prenatal developing cerebrum. |
| Keywords | Protein deimination, Post-translational modification enzyme, Microglial cells, Central nervous system, Gene expression |
| Adress and Contact Informations | 1Biological Science Laboratory, Meiji University, Suginami-ku, Tokyo
168-8555, Japan, 2Department of Molecular Pathology, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Tokyo 173-0015, Japan * Author for correspondence; e-mail: hiro_asa@kisc.meiji.ac.jp, tel: +81 3 5300 1251, fax: +81 3 5300 1203 |
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| DOI: 10.2478/s11658-007-0024-z Volume 12 (2007) pp 545 - 555 | |
| Title | TRACKING CHROMATIN STATES USING CONTROLLED DNase I TREATMENT AND REAL-TIME PCR |
| Authors | Rui Pires Martins1, Adrian E. Platts1,2 and Stephen A. Krawetz1-3 * |
| Abstract | A novel approach to DNase I-sensitivity analysis was applied to examining genes of the spermatogenic pathway, reflective of the substantial morphological and genomic changes that occur during this program of differentiation. A new real-time PCR-based strategy that considers the nuances of response to nuclease treatment was used to assess the nuclease susceptibility through differentiation. Data analysis was automated with the K-Lab PCR algorithm, facilitating the rapid analysis of multiple samples while eliminating the subjectivity usually associated with Ct analyses. The utility of this assay and analytical paradigm as applied to nuclease-sensitivity mapping is presented. |
| Keywords | DNase I-sensitivity, Differentiation, Spermatogenesis, Method |
| Adress and Contact Informations | 1Center for Molecular Medicine and Genetics, 2Department of Obstetrics and Gynecology, Wayne State University School of Medicine and 3Institute for Scientific Computing, Wayne State University, Detroit, Michigan, USA * Author for correspondence: Charlotte B. Failing Professor of Fetal Therapy and Diagnosis, 253 C.S. Mott Center; 275 East Hancock; Detroit, MI, USA 48201, tel: 313- 577-6770, fax: 313-577-8554, e- mail: steve@compbio.med.wayne.edu |
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| DOI: 10.2478/s11658-007-0022-1 Volume 12 (2007) pp 556 - 572 | |
| Title | SILENCING OF THE TYPE 1 INSULIN-LIKE GROWTH FACTOR RECEPTOR INCREASES THE SENSITIVITY TO APOPTOSIS AND INHIBITS INVASION IN HUMAN LUNG ADENOCARCINOMA A549 CELLS |
| Authors | Zhiyuan Ma1, 2, Aiqiang Dong1, *, Minjian Kong1 and Jianfang Qian1 |
| Abstract | The type 1 insulin-like growth factor receptor (IGF-1R), which is over-expressed or activated in many human cancers, including lung cancer, mediates cancer cell proliferation and metastasis. Several studies indicate that blocking IGF-1R expression can inhibit tumor cell proliferation and metastasis. In this study, inhibition of the endogenous IGF-1R by recombinant adenoviruses encoding short hairpin RNAs against IGF-1R was found to significantly suppress IGF-1R expression, arrest the cell cycle, enhance the apoptotic response, and inhibit proliferation, adhesion, invasion and migration in A549 cells. Moreover, silencing IGF-1R decreases the expression of invasive-related genes including matrix metalloproteinase-2 (MMP-2), MMP-9, and urokinaseplasminogen activator (u-PA), and the phosphorylation of Akt and ERK1/2. These results suggest that the silencing of IGF-1R has the potential to be an effective cancer gene therapy strategy for human lung cancer. |
| Keywords | IGF-1R, Lung cancer, Short hairpin RNA, MMPs, Apoptosis, Metastasis |
| Adress and Contact Informations | 1Department of Cardiothoracic Surgery, Second Affiliated Hospital, School of
Medicine, Zhejiang University, Hangzhou, 310009, China, 2Department of Thoracic and Cardiovascular Surgery, Shanghai Jiao Tong University Affiliated First People’s Hospital, Shanghai, 200080, China * Author for correspondence; e-mail: dr_dongaiqiang@sina.com, tel: (86) 571-87783641, fax: (86) 571-87022660 |
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| DOI: 10.2478/s11658-007-0026-x Volume 12 (2007) pp 573 - 583 | |
| Title | THE DIFFERENTIAL EXPRESSION OF RIBOSOMAL 18S RNA PARALOG GENES FROM THE CHAETOGNATH Spadella cephaloptera |
| Authors | Roxane-Marie Barthelemy1*, Michel Grino2, Pierre Pontarotti3, Jean-Paul Casanova1 and Eric Faure1 |
| Abstract | Chaetognaths constitute a small marine phylum of approximately 120 species. Two classes of both 18S and 28S rRNA gene sequences have been evidenced in this phylum, even though significant intraindividual variation in the sequences of rRNA genes is unusual in animal genomes. These observations led to the hypothesis that this unusual genetic characteristic could play one or more physiological role(s). Using in situ hybridization on the frontal sections of the chaetognath Spadella cephaloptera, we found that the 18S Class I genes are expressed in the whole body, with a strong expression throughout the gut epithelium, whereas the expression of the 18S Class II genes is restricted to the oocytes. Our results could suggest that the paralog products of the 18S Class I genes are probably the “housekeeping” 18S rRNAs, whereas those of class II would only be essential in specific tissues. These results provide support for the idea that each type of 18S paralog is important for specific cellular functions and is under the control of selective factors. |
| Keywords | 18S, Chaetognath, Spadella cephaloptera, In situ hybridization, Duplication, Expression pattern, rRNA paralogs |
| Adress and Contact Informations | 1Biodiversity and Environment, case 18, 3 Place V. Hugo, Université de
Provence, 13331 Marseille cedex 3, France, 2Inserm UMR 626, UFR de Medecine secteur Timone, 27 Bd Jean Moulin, 13385 Marseille cedex 5, France, 3Phylogenomic Laboratory, EA Evolution Biologique 3781, Université de Provence, Case 19, 13331 Marseille cedex 3, France Author for correspondence; e-mail: roxane.barthelemy@up.univ-mrs.fr, tel: +33 491 10 63 30, fax: +33 491 10 62 65 |
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| DOI: 10.2478/s11658-007-0029-7 Volume 12 (2007) pp 584 - 594 | |
| Title | THE COMPLETE STRUCTURE OF THE CUCUMBER (Cucumis sativus L.) CHLOROPLAST GENOME: ITS COMPOSITION AND COMPARATIVE ANALYSIS |
| Authors | Wojciech Pląder1*, Yasushi Yukawa2, Masahiro Sugiura 2 and Stefan Malepszy1 |
| Abstract | The complete nucleotide sequence of the cucumber (C. sativus L. var. Borszczagowski) chloroplast genome has been determined. The genome is composed of 155,293 bp containing a pair of inverted repeats of 25,191 bp, which are separated by two single-copy regions, a small 18,222-bp one and a large 86,688-bp one. The chloroplast genome of cucumber contains 130 known genes, including 89 protein-coding genes, 8 ribosomal RNA genes (4 rRNA species), and 37 tRNA genes (30 tRNA species), with 18 of them located in the inverted repeat region. Of these genes, 16 contain one intron, and two genes and one ycf contain 2 introns. Twenty-one small inversions that form stem-loop structures, ranging from 18 to 49 bp, have been identified. Eight of them show similarity to those of other species, while eight seem to be cucumber specific. Detailed comparisons of ycf2 and ycf15, and the overall structure to other chloroplast genomes were performed. |
| Keywords | Organelle, Gene order |
| Adress and Contact Informations | 1Warsaw Agricultural University, Faculty of Horticulture and Landscape
Architecture, Department of Plant Genetics, Breeding and Biotechnology,
Nowoursynowska 159, 02-776 Warsaw, Poland, 2Graduate School of Natural Sciences, Nagoya City University, Mizuho, Nagoya 467-8501, Japan *Author for correspondence; e-mail: wojciech_plader@sggw.pl, tel/fax: +48-22-59-321-52 |
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| DOI: 10.2478/s11658-007-0027-9 Volume 12 (2007) pp 595 - 603 | |
| Title | THE EXPRESSION OF ENDOTHELIN TYPE A AND B RECEPTORS IN THE LATERAL WALL OF THE MOUSE COCHLEA |
| Authors | Yan Luo1, Yuedi Tang*1, Qingjie Xia2 and Jin Liu3 |
| Abstract | Endothelin (ET), originally characterized as a vasoconstrictive peptide, has been found to have many different biological functions, including acting as a local hormonal regulator of pressure, fluid, ions and neurotransmitters in the inner ear. The objective of this study was to examine and quantify the mRNA expression of the endothelin type A and B receptors (ETAR and ETBR) in the strial vascularies (StV) and non-strial tissues (NSt) of the cochlear lateral wall using the real-time quantitative reverse transcriptionpolymerase chain reaction (RT-PCR) technique. The mouse tissue samples were harvested and RNA was extracted. RT was performed to obtain cDNA, and then the mRNA expression of each gene was measured via real-time PCR. We found that both receptor subtypes were expressed in the cochlear lateral wall, with a predominance of ETAR over ETBR. We showed that the mRNA expression of the two receptor subtypes was higher in the StV with a 1.8 times higher level of ETAR and an 8.1 times higher level of ETBR mRNAs than in the adjacent NSt of the lateral wall tissue. This study shows the existence and the quantity of ET receptor subtypes in the StV and NSt of the mouse cochlea. Our results suggest that an endothelin-mediated response via two different receptors, ETAR and ETBR, may play an important role in the physiological functions of the cochlear lateral wall by maintaining the homeostatic environment of the cochlea. |
| Keywords | ETAR, ETBR, Real time quantitative RT-PCR, Cochlea |
| Adress and Contact Informations | 1Department of Otorhinolaryngology, West China Hospital of Sichuan
University, Chengdu, Sichuan, China, 2Department of Ophthalmology, Laboratory of Molecular Biology, West China Hospital of Sichuan University, Chengdu, Sichuan, China, 3Department of Anesthesiology and Critical Care Medicine, West China Hospital of Sichuan University, Chengdu, Sichuan, China * Author for correspondence: Yuedi Tang, Department of Otorhinolaryngology, West China Hospital of Sichuan University, No. 37 Guo-Xue-Xiang, Chengdu, Sichuan 610041, P. R. Ch ina, e-mail: tangyd@hotmail.com |
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| DOI: 10.2478/s11658-007-0028-8 Volume 12 (2007) pp 604 - 620 | |
| Title | BRAIN PROTEINS INTERACTING WITH THE TETRAMERIZATION REGION OF NON-ERYTHROID ALPHA SPECTRIN |
| Authors | Younsang Oh and Leslie W.-M. Fung* |
| Abstract | The N-terminal region of non-erythroid alpha spectrin (SpαII) is responsible for interacting with its binding partner, beta spectrin, to form functional spectrin tetramers. We used a yeast-two-hybrid system, with an N-terminal segment of alpha spectrin representing the functional tetramerization site, as a bait to screen human brain c-DNA library for proteins that interact with the alpha spectrin segment. In addition to several beta spectrin isoforms, we identified 14 proteins that interact with SpαII. Seven of the 14 were matched to 6 known proteins: Duo protein, Lysyl-tRNA synthetase, TBP associated factor 1, two isoforms (b and c) of a protein kinase A interacting protein and Zinc finger protein 333 (2 different segments). Four of the 6 proteins are located primarily in the nucleus, suggesting that spectrin plays important roles in nuclear functions. The remaining 7 proteins were unknown to the protein data base. Structural predictions show that many of the 14 proteins consist of a large portion of unstructured regions, suggesting that many of these proteins fold into a rather flexible conformation. It is interesting to note that all but 3 of the 14 proteins are predicted to consist of one to four coiled coils (amphiphilic helices). A mutation in SpαII, V22D, which interferes with the coiled coil bundling of SpαII with beta spectrin, also affects SpαII interaction with Duo protein, TBP associated factor 1 and Lysyl-tRNA synthetase, suggesting that they may compete with beta spectrin for interaction with SpαII. Future structural and functional studies of these proteins to provide interaction mechanisms will no doubt lead to a better understanding of brain physiology and pathophysiology. |
| Keywords | Spectrin, Tetramerization site, Protein-protein interaction, Yeasttwo hybrid system, Brain protein, Spectrin mutation |
| Adress and Contact Informations | Department of Chemistry, University of Illinois at Chicago, 845 W. Taylor
Street, MC 111, Chicago, IL 60607, USA * Author for correspondence; e-mail: lfung@uic.edu, tel: (312) 355-5516, fax: (312) 996- 0 431 |
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| DOI: 10.2478/s11658-007-0036-8 Volume 12 (2007) pp 621 - 632 | |
| Title | CYTOSOLIC PHOSPHOLIPASE A2 REGULATION IN THE HIBERNATING THIRTEEN-LINED GROUND SQUIRREL |
| Authors | Ashley K. Woods and Kenneth B. Storey* |
| Abstract | Cytosolic calcium-dependent phospholipase A2 (cPLA2) has multiple roles including production of arachidonic acid (a key player in cellular signaling pathways) and membrane remodeling. Additionally, since catabolism of arachidonic acid generates free radicals, the enzyme is also implicated in ischemic injury to mammalian organs. Regulation of cPLA2 could be important in the suppression and prioritization of cellular pathways in animals that undergo reversible transitions into hypometabolic states. The present study examines the responses and regulation of cPLA2 in skeletal muscle and liver of hibernating thirteen-lined ground squirrels, Spermophilus tridecemlineatus. cPLA2 activity decreased significantly by 43% in liver during hibernation, compared with euthermic controls, and Km values for arachidonoyl thio-PC substrate fell in both organs during hibernation to 61% in liver and 28% in muscle of the corresponding euthermic value. To determine whether these responses were due to a change in the phosphorylation state of the enzyme, Western blotting was employed using antibodies recognizing phospho-Ser505 on α-cPLA2. The amount of phosphorylated α-cPLA2 in hibernator liver was just 38% of the value in euthermic liver. Furthermore, incubation of liver extracts under conditions that enhanced protein phosphatase action caused a greater reduction in the detectable amount of phospho-Ser505 enzyme content in euthermic, versus hibernator, extracts. The data are consistent with a suppression of cPLA2 function during torpor via enzyme dephosphorylation, an action that may contribute to the welldeveloped ischemia tolerance and lack of oxidative damage found in hibernating species over cycles of torpor and arousal. |
| Keywords | Metabolic rate depression, Signaling, Arachidonic acid production, Reversible phosphorylation, Spermophilus tridecemlineatus |
| Adress and Contact Informations | Institute of Biochemistry and Department of Biology, Carleton University,
1125 Colonel By Drive, Ottawa, Ontario, Canada K1S 5B6 * Author for correspondence; e-mail: kenneth_storey@carleton.ca, tel: 1 613 520-3678, fax: 1 613 520-3745 |
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Cellular & Molecular Biology Letters
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University of Wrocław
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University of Wrocław
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51-148 Wrocław, Poland
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+48 71 375 6208 or
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