CBL and CaM have sequence similarity due to Ca
2+ binding EF-hands. The size of
these proteins ranges between 23 and 26 kDa, which include 4 EF-hands (Batistic
et al. 2011). Structurally CBL consists of catalytic N-terminal region containing
targeting sites, myristoylation and palmitoylation motifs, and C-terminal domain of
regulatory nature. These motifs reported in CBL1 and CBL9 which anchor CIPK
towards the plasma membrane. Experimental studies revealed that when CBL1 and
CBL9 interact with CIPK26, then this complex enhances functionality of NADPH
oxidase RBOHF through phosphorylation (Drerup et al. 2013; Kimura et al. 2013). It
also contains region of 24 hydrophobic amino acid residues, NAF/FISL motif is
highly conserved in CIPK (Meena and Vadassery 2015). Membrane associated
protein substrates undergo phosphorylation due to the formation of CIPK complex.
CBL targeted CIPK have cellular location based function, hence same kinases able
to perform different function according to location and condition. CBL–CIPK
complex becomes very specific in response to different stresses. Its signalling
pathway is regulated by complex mechanisms in plant cells involving crosstalk
with other signalling pathways (Yu et al. 2014).
Genes involved in the CBL–CIPK pathway were highly upregulated in Camellia
sinensis upon mild infestation by green leafhopper (Empoasca vitis) by herbivory
attack. The expression of a CBL-interacting protein kinase 19 gene CsEv9 significantly increased in the Fuzao2 tea cultivar infested by the tea leafhopper
(by approximately 18-fold with respect to the controls), providing the first evidence
for the involvement of the CBL–CIPK pathway in response to herbivory (Yang et al.
2011).
16.4.4 Calcium Dependent Protein Kinases
CDPKs are multifunctional proteins with Ca
2+ binding domain and kinase activity
(Tena et al. 2011). CDPK has a noteworthy role of Ca
2+ binding and herbivoreinduced signalling cascades during plant–herbivory interaction. It converts the event
of Ca
2+ signals into phosphorylation and kinase activities in plants. CDPKs
investigated in Protista kingdom also other than Plantae kingdom (Ozturk et al.
2002; Seki et al. 2002). It is reported in many plant species mainly in Arabidopsis
thaliana (Cheng et al. 2002), Oryza sativa (Ray et al. 2007), Triticum aestivum
(Li et al. 2008), Zea mays (Kong et al. 2013), Populus trichocarpa (Zuo et al. 2013),
Gossypium raimondii (Liu et al. 2014), Solanum lycopersicum (Hu et al. 2016),
Cucumis sativus (Xu et al. 2015), and Ananas comosus (Zhang et al. 2020). In plants,
this sensor is localized in Ca
2+ storing subcellular organelles plasma membrane,
cytosol, mitochondria, peroxisome, endoplasmic reticulum, and nucleus for quick
response (Chehab et al. 2004; Dammann et al. 2003; Sugiyama et al. 2000). CDPKs
proteins size ranges from ~40 to 90 kDa. It contains 5 domains with highly
conserved Ser-Thr kinase catalytic region. Next to the kinase region, junction region
continued which has pretented substrate activity and autoinhibitory function. Junction region interacts with active site and impedes its kinase activity. Adjacent to it,
CaM-like domain (CLD) is present, which consists of 4 EF-hands to bind with the
500
A. Kumar et al.
2+ binding EF-hands. The size of
these proteins ranges between 23 and 26 kDa, which include 4 EF-hands (Batistic
et al. 2011). Structurally CBL consists of catalytic N-terminal region containing
targeting sites, myristoylation and palmitoylation motifs, and C-terminal domain of
regulatory nature. These motifs reported in CBL1 and CBL9 which anchor CIPK
towards the plasma membrane. Experimental studies revealed that when CBL1 and
CBL9 interact with CIPK26, then this complex enhances functionality of NADPH
oxidase RBOHF through phosphorylation (Drerup et al. 2013; Kimura et al. 2013). It
also contains region of 24 hydrophobic amino acid residues, NAF/FISL motif is
highly conserved in CIPK (Meena and Vadassery 2015). Membrane associated
protein substrates undergo phosphorylation due to the formation of CIPK complex.
CBL targeted CIPK have cellular location based function, hence same kinases able
to perform different function according to location and condition. CBL–CIPK
complex becomes very specific in response to different stresses. Its signalling
pathway is regulated by complex mechanisms in plant cells involving crosstalk
with other signalling pathways (Yu et al. 2014).
Genes involved in the CBL–CIPK pathway were highly upregulated in Camellia
sinensis upon mild infestation by green leafhopper (Empoasca vitis) by herbivory
attack. The expression of a CBL-interacting protein kinase 19 gene CsEv9 significantly increased in the Fuzao2 tea cultivar infested by the tea leafhopper
(by approximately 18-fold with respect to the controls), providing the first evidence
for the involvement of the CBL–CIPK pathway in response to herbivory (Yang et al.
2011).
16.4.4 Calcium Dependent Protein Kinases
CDPKs are multifunctional proteins with Ca
2+ binding domain and kinase activity
(Tena et al. 2011). CDPK has a noteworthy role of Ca
2+ binding and herbivoreinduced signalling cascades during plant–herbivory interaction. It converts the event
of Ca
2+ signals into phosphorylation and kinase activities in plants. CDPKs
investigated in Protista kingdom also other than Plantae kingdom (Ozturk et al.
2002; Seki et al. 2002). It is reported in many plant species mainly in Arabidopsis
thaliana (Cheng et al. 2002), Oryza sativa (Ray et al. 2007), Triticum aestivum
(Li et al. 2008), Zea mays (Kong et al. 2013), Populus trichocarpa (Zuo et al. 2013),
Gossypium raimondii (Liu et al. 2014), Solanum lycopersicum (Hu et al. 2016),
Cucumis sativus (Xu et al. 2015), and Ananas comosus (Zhang et al. 2020). In plants,
this sensor is localized in Ca
2+ storing subcellular organelles plasma membrane,
cytosol, mitochondria, peroxisome, endoplasmic reticulum, and nucleus for quick
response (Chehab et al. 2004; Dammann et al. 2003; Sugiyama et al. 2000). CDPKs
proteins size ranges from ~40 to 90 kDa. It contains 5 domains with highly
conserved Ser-Thr kinase catalytic region. Next to the kinase region, junction region
continued which has pretented substrate activity and autoinhibitory function. Junction region interacts with active site and impedes its kinase activity. Adjacent to it,
CaM-like domain (CLD) is present, which consists of 4 EF-hands to bind with the
500
A. Kumar et al.