A salt-activated inositol 1,3,4,5-tetrakisphosphate 3-phosphatase at the inner surface of the human erythrocyte membrane

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A salt-activated inositol 1,3,4,5-tetrakisphosphate 3-phosphatase at the inner surface of the human erythrocyte membrane. / Estrada-Garcia, T.; Craxton, A.; Kirk, C. J.; Michell, R. H.

In: Proceedings of the Royal Society B: Biological Sciences, Vol. 244, No. 1309, 01.01.1991, p. 63-68.

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@article{e4ecb197221c4dfcb040aba930df5ca0,
title = "A salt-activated inositol 1,3,4,5-tetrakisphosphate 3-phosphatase at the inner surface of the human erythrocyte membrane",
abstract = "The localization of the human erythrocyte membrane Ins(1,3,4,5)P4 3-phosphatase was investigated by saponin permeabilization of resealed 'isoionic' erythrocyte ghosts. This enzyme is active at the inner face of the plasma membrane, at the same site as a specific 5-phosphatase that degrades both Ins(1,4,5)P3 and Ins(1,3,4,5)P4. In the presence of EDTA, Ins(1,4,5)P3 was the only product of Ins(1,3,4,5)P4 metabolism. However, when Mg2+ was present both the 5-phosphatase and the 3-phosphatase attacked Ins(1,3,4,5)P4, directly forming Ins(1,3,4)P3 and Ins(1,4,5)P3; some Ins(1,4)P2 was also formed as a product of 5-phosphatase attack on the liberated Ins(1,4,5)P3 The Ins(1,3,4,5)P4 3-phosphatase was potently activated by KCl, thus making the route of metabolism of Ins(1,3,4,5)P4 by erythrocyte ghosts strikingly sensitive to variations in ionic strength: at 'cytosolic' K+ and Mg2+ levels, 3-phosphatase activity slightly predominated over 5-phosphatase. Ins(1,3,4,5)P4 3-phosphatase was potently inhibited by Ins(1,3,4,5,6)P5 and InsP6 at levels lower than those often observed within cells. This leaves open the question as to whether the cellular function of inositol polyphosphate 3-phosphatase is to participate in a physiological cycle that interconverts Ins(1,3,4,5)P4 and Ins(1,4,5)P3 or to metabolize other inositol polyphosphates in the cytosol compartment of cells.",
author = "T. Estrada-Garcia and A. Craxton and Kirk, {C. J.} and Michell, {R. H.}",
year = "1991",
month = jan,
day = "1",
doi = "10.1098/rspb.1991.0052",
language = "English",
volume = "244",
pages = "63--68",
journal = "Royal Society of London. Proceedings B. Biological Sciences",
issn = "0962-8452",
publisher = "The Royal Society",
number = "1309",

}

RIS

TY - JOUR

T1 - A salt-activated inositol 1,3,4,5-tetrakisphosphate 3-phosphatase at the inner surface of the human erythrocyte membrane

AU - Estrada-Garcia, T.

AU - Craxton, A.

AU - Kirk, C. J.

AU - Michell, R. H.

PY - 1991/1/1

Y1 - 1991/1/1

N2 - The localization of the human erythrocyte membrane Ins(1,3,4,5)P4 3-phosphatase was investigated by saponin permeabilization of resealed 'isoionic' erythrocyte ghosts. This enzyme is active at the inner face of the plasma membrane, at the same site as a specific 5-phosphatase that degrades both Ins(1,4,5)P3 and Ins(1,3,4,5)P4. In the presence of EDTA, Ins(1,4,5)P3 was the only product of Ins(1,3,4,5)P4 metabolism. However, when Mg2+ was present both the 5-phosphatase and the 3-phosphatase attacked Ins(1,3,4,5)P4, directly forming Ins(1,3,4)P3 and Ins(1,4,5)P3; some Ins(1,4)P2 was also formed as a product of 5-phosphatase attack on the liberated Ins(1,4,5)P3 The Ins(1,3,4,5)P4 3-phosphatase was potently activated by KCl, thus making the route of metabolism of Ins(1,3,4,5)P4 by erythrocyte ghosts strikingly sensitive to variations in ionic strength: at 'cytosolic' K+ and Mg2+ levels, 3-phosphatase activity slightly predominated over 5-phosphatase. Ins(1,3,4,5)P4 3-phosphatase was potently inhibited by Ins(1,3,4,5,6)P5 and InsP6 at levels lower than those often observed within cells. This leaves open the question as to whether the cellular function of inositol polyphosphate 3-phosphatase is to participate in a physiological cycle that interconverts Ins(1,3,4,5)P4 and Ins(1,4,5)P3 or to metabolize other inositol polyphosphates in the cytosol compartment of cells.

AB - The localization of the human erythrocyte membrane Ins(1,3,4,5)P4 3-phosphatase was investigated by saponin permeabilization of resealed 'isoionic' erythrocyte ghosts. This enzyme is active at the inner face of the plasma membrane, at the same site as a specific 5-phosphatase that degrades both Ins(1,4,5)P3 and Ins(1,3,4,5)P4. In the presence of EDTA, Ins(1,4,5)P3 was the only product of Ins(1,3,4,5)P4 metabolism. However, when Mg2+ was present both the 5-phosphatase and the 3-phosphatase attacked Ins(1,3,4,5)P4, directly forming Ins(1,3,4)P3 and Ins(1,4,5)P3; some Ins(1,4)P2 was also formed as a product of 5-phosphatase attack on the liberated Ins(1,4,5)P3 The Ins(1,3,4,5)P4 3-phosphatase was potently activated by KCl, thus making the route of metabolism of Ins(1,3,4,5)P4 by erythrocyte ghosts strikingly sensitive to variations in ionic strength: at 'cytosolic' K+ and Mg2+ levels, 3-phosphatase activity slightly predominated over 5-phosphatase. Ins(1,3,4,5)P4 3-phosphatase was potently inhibited by Ins(1,3,4,5,6)P5 and InsP6 at levels lower than those often observed within cells. This leaves open the question as to whether the cellular function of inositol polyphosphate 3-phosphatase is to participate in a physiological cycle that interconverts Ins(1,3,4,5)P4 and Ins(1,4,5)P3 or to metabolize other inositol polyphosphates in the cytosol compartment of cells.

UR - http://www.scopus.com/inward/record.url?scp=0025782487&partnerID=8YFLogxK

U2 - 10.1098/rspb.1991.0052

DO - 10.1098/rspb.1991.0052

M3 - Article

AN - SCOPUS:0025782487

VL - 244

SP - 63

EP - 68

JO - Royal Society of London. Proceedings B. Biological Sciences

JF - Royal Society of London. Proceedings B. Biological Sciences

SN - 0962-8452

IS - 1309

ER -