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Inositol tetrakisphosphate as a second messenger: Confusions, contradictions, and a potential resolution
Author(s) -
Irvine Robin F.
Publication year - 1991
Publication title -
bioessays
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.175
H-Index - 184
eISSN - 1521-1878
pISSN - 0265-9247
DOI - 10.1002/bies.950130810
Subject(s) - second messenger system , inositol , resolution (logic) , biology , computational biology , chemistry , biochemistry , computer science , artificial intelligence , signal transduction , receptor
The second messenger function of inositol 1,4,5‐ trisphosphate (Ins P 3 ) is now well‐defined – it mobilizes Ca 2+ from intracellular stores so that cytosolic Ca 2+ increases. However, the function of inositol 1,3,4,5‐ tetrakisphosphate (Ins P 4 ) has proved much more difficult to fathom, as it has been reported to exert a wide variety of effects in a collection of experimental systems. In this review, a proposed molecular mechanism for Ins P 4 actions is discussed; it is suggested that Ins P 4 is the second messenger that controls Ca 2+ entry into cells, and that it does so by binding to a receptor which itself interacts, directly or Indirectly, with the receptor for Ins P 3 It is proposed that this is Ins P 4 's true physiological function, but the mechanism by which it exerts this function has led to confusing data concerning its action, and also to some misconceptions about how inositol phosphates control Ca 2+ entry.