PCaPs, possible regulators of PtdInsP signals on plasma membrane.
In plants, Ca(2+), phosphatidylinositol phosphates (PtdInsPs) and inositol phosphates are major components of intracellular signaling. Several kinds of proteins and enzymes, such as calmodulin (CaM), protein kinase, protein phosphatase, and the Ca(2+) channel, mediate the signaling. Two new Ca(2+)-binding proteins were identified from Arabidopsis thaliana and named PCaP1 and PCaP2 [plasma membrane (PM)-associated Ca(2+) (cation)-binding protein 1 and 2]. PCaP1 has an intrinsically disordered region in the central and C-terminal parts. The PCaP1 gene is expressed in most tissues and the PCaP2 gene is expressed predominantly in root hairs and pollen tubes. We recently demonstrated that these proteins are N-myristoylated, stably anchored in the PM, and are bound with phosphatidylinositol phosphates, especially PtdInsP2s. Here we propose a model for the switching mechanism of Ca (2+)-signaling mediated by PtdInsPs. Ca(2+) forms a complex with CaM (Ca(2+)-CaM) when there is an increase in the cytosol free Ca(2+). The binding of PCaPs with Ca(2+)-CaM causes PCaPs to release PtdInsPs. Until the release of PtdInsPs, the signaling is kept in the resting state.
Kato
Mariko
M
Graduate School of Bioagricultural Sciences; Nagoya University, Nagoya, Japan.
Nagasaki-Takeuchi
Nahoko
N
Ide
Yuki
Y
Tomioka
Rie
R
Maeshima
Masayoshi
M
J Biol Chem. 2009 Mar 20;284(12):7455-64
19106096
Plant Cell. 2007 Mar;19(3):877-89
17337629
EMBO J. 2004 Feb 25;23(4):712-8
14765114
FEBS Lett. 2006 Apr 3;580(8):2041-5
16542654
J Exp Bot. 2007;58(5):1173-83
17264065
FEBS J. 2008 May;275(9):2267-82
18397324
Annu Rev Biophys. 2008;37:175-95
18573078
Plant Cell. 2006 Dec;18(12):3519-34
17172355
Plant Cell. 2008 Feb;20(2):367-80
18281506
Plant Cell. 2002 Oct;14(10):2399-412
12368494
Annu Rev Plant Biol. 2003;54:265-306
14502992
Trends Plant Sci. 2000 Jun;5(6):252-8
10838616
Cell. 2007 Dec 14;131(6):1047-58
18083096
Plant Physiol. 2009 Feb;149(2):1127-40
19052153
Plant Physiol. 2008 Aug;147(4):1690-8
18583529
J Biochem. 2008 Oct;144(4):487-97
18664522
Trends Plant Sci. 2005 Aug;10(8):383-9
16023399
J Biochem. 2007 Aug;142(2):201-11
17575286
Plant Cell Physiol. 2010 Mar;51(3):366-79
20061304
Plant Physiol. 2008 Jun;147(2):624-35
18408046
Pflugers Arch. 2007 Oct;455(1):45-53
17588168
J Biol Chem. 2006 Sep 29;281(39):28831-6
16893883