Biology Reference
In-Depth Information
AtPep1 (HAMP)
Binding with
At PepR1
(guanylyl cyclase)
GMP
GTP
Activation
CNG channel
Ca
2+
influx
Cytosolic Ca
2+
elevation
Ca
2+
signature
Activation
Plant immune responses
Fig. 4.2
Activation of CNG channel-mediated Ca
2+
infl ux by the HAMP AtPep1 (Adapted from
Qi et al.
2010
)
AtPepR1 has guanylyl cyclase activity and this activity generates cGMP from GTP.
The cGMP activates CNGC2-dependent cytosolic Ca
2+
elevation (Qi et al.
2010
).
AtPep-dependent expression of defense genes such as PDF1.2, MPK3, and
WRKY33, is mediated by the Ca
2+
signaling pathway associated with AtPep
peptides and their receptor (Fig.
4.2
; Qi et al.
2010
). These studies indicate that
downstream from AtPep and AtPepR1 in a signaling cascade, the cGMP-activated
channel CNGC2 is involved in AtPep- and AtPepR1-dependent inward Ca
2+
conductance and resulting cytosolic Ca
2+
elevation.
4.3.3
Glutamate Receptor-Like Ion Channels
Glutamate receptors (GLRs) comprise another class of ion channel that might
provide a calcium-permeable pathway across the plasma membrane (Sanders et al.
2002
; Vatsa et al.
2011
; Price et al.
2012
; Vincill et al.
2012
). The glutamate recep-
tors are ligand-gated non-selective cation channels permeable to calcium (Demidchik
et al.
2002
,
2004
; Kang et al.
2006b
; Tapken and Hollmann
2008
; Tikhonov and
Search WWH ::
Custom Search