TY - JOUR
T1 - Inositol 1,4,5-trisphosphate and guanine nucleotides activate calcium release from endoplasmic reticulum via distinct mechanisms
AU - Chueh, S. H.
AU - Gill, D. L.
N1 - Copyright:
Copyright 2004 Elsevier B.V., All rights reserved.
PY - 1986
Y1 - 1986
N2 - A sensitive and specific guanine nucleotide regulatory process has recently been shown to rapidly mediate a substantial release of Ca2+ from endoplasmic reticulum within the N1E-115 neuronal cell line (Gill, D.L., Ueda, T., Chueh, S.H., and Noel, M.W. (1986) Nature 320, 461-464). The relationship between this mechanism and Ca2+ efflux mediated by the intracellular regulator inositol 1,4,5-trisphosphate (IP3) has been investigated. Using saponin-permeabilized N1E-115 cells, studies reveal a number of distinctions between the activation of Ca2+ release mediated by GTP and IP3. Thus, the GTP-mediated Ca2+ release process is specifically activated by polyethylene glycol which increases both GTP sensitivity and the extent of GTP-activated Ca2+ release; in contrast, IP3-dependent Ca2+ release is unaffected by polyethylene glycol. The nonhydrolyzable GTP analogue guanosine 5'-O-(3-thio)triphosphate, which completely inhibits GTP-mediated Ca2+ release, does not alter release mediated by IP3. Decreasing the release temperature from 37 to 4°C decreases IP3-activated Ca2+ release by only 20%, whereas the action of GTP on Ca2+ release is abolished at 4° C. Activation of Ca2+ release by IP3 is completely inhibited by increasing free Ca2+ from 0.1 to 10 μM, whereas the fraction of GTP-dependent Ca2+ release (approximately 50% of ionophore-releasable Ca2+) remains unaltered with increasing free Ca2+. These distinctions between IP3- and GTP-mediated Ca2+ release indicate that the two effectors function via distinct mechanisms to activate Ca2+ release; however, they do not preclude the possibility that coupling between the two mechanisms can occur or that a common Ca2+-translocating pathway activated by both effectors exists.
AB - A sensitive and specific guanine nucleotide regulatory process has recently been shown to rapidly mediate a substantial release of Ca2+ from endoplasmic reticulum within the N1E-115 neuronal cell line (Gill, D.L., Ueda, T., Chueh, S.H., and Noel, M.W. (1986) Nature 320, 461-464). The relationship between this mechanism and Ca2+ efflux mediated by the intracellular regulator inositol 1,4,5-trisphosphate (IP3) has been investigated. Using saponin-permeabilized N1E-115 cells, studies reveal a number of distinctions between the activation of Ca2+ release mediated by GTP and IP3. Thus, the GTP-mediated Ca2+ release process is specifically activated by polyethylene glycol which increases both GTP sensitivity and the extent of GTP-activated Ca2+ release; in contrast, IP3-dependent Ca2+ release is unaffected by polyethylene glycol. The nonhydrolyzable GTP analogue guanosine 5'-O-(3-thio)triphosphate, which completely inhibits GTP-mediated Ca2+ release, does not alter release mediated by IP3. Decreasing the release temperature from 37 to 4°C decreases IP3-activated Ca2+ release by only 20%, whereas the action of GTP on Ca2+ release is abolished at 4° C. Activation of Ca2+ release by IP3 is completely inhibited by increasing free Ca2+ from 0.1 to 10 μM, whereas the fraction of GTP-dependent Ca2+ release (approximately 50% of ionophore-releasable Ca2+) remains unaltered with increasing free Ca2+. These distinctions between IP3- and GTP-mediated Ca2+ release indicate that the two effectors function via distinct mechanisms to activate Ca2+ release; however, they do not preclude the possibility that coupling between the two mechanisms can occur or that a common Ca2+-translocating pathway activated by both effectors exists.
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M3 - Article
C2 - 3533912
AN - SCOPUS:0023019686
SN - 0021-9258
VL - 261
SP - 13883
EP - 13886
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 30
ER -