Important note: Information in this article was accurate in 1990. The state of the art may have changed since the publication date.
INVOLVEMENT OF G PROTEINS AND CAMP-DEPENDENT PROTEIN KINASES IN THE SIGNAL TRANSDUCTION PATHWAY FOR INTERLEUKIN 1
Diss Abstr Int [B]; 51(2):650 1990. Unique Identifier : AIDSLINE ICDB/90668489 Chedid M; Wake Forest Univ., Bowman Gray Sch. of Medicine
Abstract:
Interleukin 1 (IL1) is a macrophage-derived cytokine that stimulates a broad spectrum of immune and inflammatory responses. The main objective of this thesis is to delineate the steps involved in the signal-transduction pathway for IL1. We characterized the IL1 receptor on human rheumatoid synovial cells. G proteins are a class of membrane associated proteins involved in the coupling and activation of hormone receptors to enzymatic effector systems such as adenylate cyclase. The possibility that a G protein may serve as an intermediate in the signal-transduction pathway linking the IL1 receptor with adenylate cyclase activation in synovial cells was examined. Pertussis toxin (PT), at nontoxic levels, markedly inhibited all three IL1-induced activation events, as well as IL1-stimulated cAMP production. The IL1-induced GTPase activity was sensitive to PT. PT also induced the ADP-ribosylation of a 46 kDa substrate in the membrane preparations from IL1-responsive cells. The possibility that cAMP-dependent protein kinases were directly involved in the mechanism of action of IL1, more specifically, in the activation of NF-kappaB, was evaluated. A 107 base-pair oligonucleotide that codes for the active portion of the skeletal muscle PKA inhibitor (PKI) was synthesized, cloned into the expression vector pSBL, and co-transfected into 70Z/3 cells in conjunction with EkappaCAT, a construct that contains the CAT reporter gene in addition to the kappa enhancer. When 70Z/3 cells were stimulated with IL1 or cAMP-elevating agents (LPS or forskolin), no CAT activity was observed. However, when 70Z/3 cells were stimulated with PMA, a protein kinase C activator, or when 70Z/3 cells were co-transfected with EkappaCAT and an inactive PKA inhibitor, and then stimulated with IL1, CAT activity was detected. Similar results were observed when YT cells were co-transfected with the PKI inhibitor oligonucleotide and a plasmid containing the CAT gene and the HIV-LTR enhancer. In conclusion, the results presented in this thesis support the notion that the binding of IL1 to its cell surface receptor activates a pertussis toxin-sensitive G protein, which in turn stimulates adenylate cyclase activity and thus increases the intracellular level of cAMP. cAMP activates cAMP-dependent protein kinase(s) which induce(s) the activation of NF-kappaB, a DNA binding protein that plays an important role in the transcriptional regulation of the HIV-LTR and the kappa Ig gene in pre-B cells. (Abstract shortened with permission of author.) (Full text available from University Microfilms International, Ann Arbor, MI, as Order No. AAD90-13780)
Keywords: Cell Line Chloramphenicol Acetyltransferase/GENETICS Enhancer Elements (Genetics) G-Proteins/*PHYSIOLOGY Human HIV/GENETICS Interleukin-1/*PHYSIOLOGY Pertussis Toxins/PHARMACOLOGY Protein Kinase C/METABOLISM Protein Kinases/*PHYSIOLOGY Receptors, Immunologic/PHYSIOLOGY Repetitive Sequences, Nucleic Acid Signal Transduction/*PHYSIOLOGY Tetradecanoylphorbol Acetate/PHARMACOLOGY Transfection THESIS 901230
M90C3721
AEGiS presents published material, reprinted with permission and neither endorses nor opposes any material. All information contained on this website, including information relating to health conditions, products, and treatments, is for informational purposes only. It is often presented in summary or aggregate form. It is not meant to be a substitute for the advice provided by your own physician or other medical professionals. Always discuss treatment options with a doctor who specializes in treating HIV.
Important note: Information in this article was accurate in 1990. The state of the art may have changed since the publication date.
