Gene Research for GO Annotation Review Falcon citations file

Gene Research for GO Annotation Review

Target

UniProt Context

=== UNIPROT METADATA ===
UniProt ID: Q9LDI3
Entry Name: CIPKO_ARATH
Gene Name: CIPK24
Protein Name: CBL-interacting serine/threonine-protein kinase 24
EC Number: 2.7.11.1
Organism: Arabidopsis thaliana (Mouse-ear cress)
NCBI Taxonomy ID: 3702
Function: Involved in the regulatory pathway for the control of intracellular Na(+) and K(+) homeostasis and salt tolerance. Activates the vacuolar H(+)/Ca(2+) antiporter CAX1 and operates in synergy with CBL4/SOS3 to activate the plasma membrane Na(+)/H(+) antiporter SOS1. CIPK serine-threonine protein kinases interact with CBL proteins. Binding of a CBL protein to the regulatory NAF domain of CIPK protein lead to the activation of the kinase in a calcium-dependent manner. Phosphorylates CBL1, CBL4 and CBL10.
Subcellular Location: Cytoplasm
Subunit: Interacts with CBL1, CBL2, CBL4/SOS3, CBL5, CBL9, CBL10 and with the protein phosphatase 2C ABI2.
======================

Research Objective

Prepare a comprehensive literature-backed research report for GO annotation review of the target gene.

Focus on:

  1. The core biochemical activity of the gene product and any substrate specificity.
  2. The activation or maturation mechanism of the protein, including proteolytic processing if relevant.
  3. The best-supported subcellular localization and complexes where the active protein functions.
  4. The strongest experimentally supported biological processes in the target organism, or in very close orthologs when transfer is justified.
  5. Which annotations appear to reflect core function versus context-specific, pleiotropic, or over-extended roles.
  6. Any evidence bearing on apoptosis, developmental cell death, neuronal roles, inflammatory signaling, pyroptosis, synaptic remodeling, protein processing, and localization to cytoplasm, cytosol, nucleus, or signaling complexes.

Output Requirements

Structure the report as:

  1. Executive summary
  2. Molecular function
  3. Biological process roles
  4. Cellular localization and complexes
  5. Annotation-risk assessment
  6. Key literature

Use citations for all substantive claims.

Gene Research Report for GO Annotation Review: CIPK24 (SOS2) in Arabidopsis thaliana

Target: CIPK24 / SOS2 (UniProt Q9LDI3; EC 2.7.11.1)

Executive summary

CIPK24 (also known as SOS2) encodes a plant-specific SnRK3/CIPK serine/threonine protein kinase that decodes salt-triggered Ca(^{2+}) signals via binding to CBL/SCaBP Ca(^{2+}) sensors (notably SOS3/CBL4 and SCaBP8/CBL10) through a conserved NAF/FISL autoinhibitory motif, leading to activation of the kinase and phosphorylation of downstream targets. The strongest, most direct molecular-function evidence supports CIPK24 as the catalytic kinase that phosphorylates and activates the plasma-membrane Na(^+)/H(^+) antiporter SOS1, thereby promoting cellular sodium ion export and Na(^+) homeostasis during salt stress. (gong2004thesos3family pages 3-4, gong2004thesos3family pages 1-2, li2023phosphatidicacid–regulatedsos2 pages 1-3, chen2023asaltstress‐activated pages 1-2)

Recent primary literature (2023) provides two major mechanistic advances that are relevant for GO review: (i) a receptor-like kinase input where GSO1/SGN3 phosphorylates SOS2 at Thr16, activating SOS2 independently of SOS3 binding and linking receptor signaling to SOS2–SOS1 function in specific root zones; and (ii) lipid signaling input where phosphatidic acid (PA) binds SOS2 at Lys57, promoting SOS2 activity and plasma-membrane accumulation, and coupling the SOS pathway to K(^+) homeostasis through SCaBP8/AKT1 regulation. (chen2023asaltstress‐activated pages 2-3, li2023phosphatidicacid–regulatedsos2 pages 1-3, li2023phosphatidicacid–regulatedsos2 media e37665a8)

Subcellularly, SOS2 alone is described in broader CIPK literature as often cytoplasmic/nucleoplasmic in GFP fusion assays; however, the active signaling complexes relevant to Na(^+) export are most strongly supported at the plasma membrane, driven by (a) lipid-modified CBL partners and (b) PA-dependent recruitment/activation of SOS2. (kudla2010calciumsignalsthe pages 11-12, li2023phosphatidicacid–regulatedsos2 pages 4-6, li2023phosphatidicacid–regulatedsos2 media e37665a8)

No evidence in the retrieved sources supports roles for CIPK24/SOS2 in animal-specific processes such as neuronal functions, inflammatory signaling, pyroptosis, synaptic remodeling, or apoptosis; similarly, no proteolytic maturation/processing mechanism is described for SOS2 in these sources. (kudla2010calciumsignalsthe pages 11-12, li2023phosphatidicacid–regulatedsos2 pages 1-3, knutova2008functionalcharacterizationof pages 14-17)

Molecular function

Core biochemical activity

Protein serine/threonine kinase activity (SnRK3/CIPK family): SOS2/CIPK24 is a Ser/Thr kinase with an N-terminal catalytic domain and a C-terminal regulatory region typical of SnRK3/CIPKs. In vitro characterization indicates dependence on divalent cations for activity (Mn(^{2+}) preferred over Mg(^{2+}) in assays) and identifies activation-loop regulatory residues, with Thr168 acting as a key activation-loop site where a phosphomimic (T168D) yields constitutive activity. (gong2004thesos3family pages 3-4, gong2004thesos3family pages 2-3)

Substrate specificity and direct targets

SOS1 (Na(^+)/H(^+) antiporter): The strongest direct substrate relationship is between SOS2 and the plasma membrane Na(^+)/H(^+) exchanger SOS1. Evidence summarized in foundational work indicates that the SOS3–SOS2 complex phosphorylates and activates SOS1, and that activated SOS2 can phosphorylate SOS1 in vitro (e.g., phosphorylation of SOS1 derived from membranes). (gong2004thesos3family pages 3-4, gong2004thesos3family pages 1-2, gong2004thesos3family pages 4-5)

SCaBP8/CBL10 (and other CBLs): SOS2 phosphorylates SOS3-like Ca(^{2+}) sensors/CBLs, including SCaBP8/CBL10. A highly cited review notes specific phosphorylation of CBL10 at Ser-237 by CIPK24. (li2023phosphatidicacid–regulatedsos2 pages 1-3, kudla2010calciumsignalsthe pages 11-12)

Additional reported/putative targets (lower-confidence for GO core MF): Older literature and reviews describe SOS2 associations with tonoplast transport processes (e.g., effects on vacuolar Na(^+)/H(^+) antiport activity and activation of CAX1 in yeast), and interactions with PP2C phosphatases ABI1/ABI2 and other stress-related proteins. These likely represent regulatory breadth but are less direct than the SOS1 substrate relationship for defining core catalytic function. (gong2004thesos3family pages 4-5, pardo2010biotechnologyofwater pages 7-9)

Activation and regulation mechanisms

1) Relief of autoinhibition via CBL binding to NAF/FISL motif: SOS2 contains an autoinhibitory FISL/NAF motif in its regulatory domain. Binding of Ca(^{2+})-loaded CBL/SCaBP proteins to this motif is proposed to relieve intramolecular inhibition and activate the kinase. (gong2004thesos3family pages 3-4, gong2004thesos3family pages 2-3)

2) Activation-loop phosphorylation: Activation-loop regulation is supported by phosphomimic substitutions at Thr168 (and related conserved positions) that yield constitutive kinase activity, supporting a phosphorylation-controlled “on” state. (gong2004thesos3family pages 3-4)

3) Upstream receptor-like kinase (GSO1/SGN3) phosphorylation at Thr16 (2023): A 2023 EMBO Journal study reports that GSO1 physically interacts with SOS2 and phosphorylates SOS2 at Thr16, activating the SOS2–SOS1 module independently of SOS3 binding; Thr16 phosphorylation is required for salt resilience in root growth in this context. (chen2023asaltstress‐activated pages 2-3, chen2023asaltstress‐activated pages 1-2)

4) Lipid regulation via phosphatidic acid binding at Lys57 (2023): A 2023 EMBO Journal study reports direct binding of PA to SOS2 at Lys57, which promotes SOS2 activity and plasma membrane localization; K57 mutation (K57G) compromises PA binding, SOS2 activation/localization, and complementation of the salt-sensitive sos2 mutant. (li2023phosphatidicacid–regulatedsos2 pages 1-3, li2023phosphatidicacid–regulatedsos2 pages 9-10, li2023phosphatidicacid–regulatedsos2 media e37665a8)

5) Negative regulation by PP2C phosphatases: SOS2 contains a PPI motif enabling interaction with PP2Cs such as ABI2, consistent with dephosphorylation-based shutdown of signaling. (gong2004thesos3family pages 4-5, knutova2008functionalcharacterizationof pages 14-17)

Biological process roles

Core, high-confidence processes (supported directly by SOS2→SOS1 mechanism)

Salt stress tolerance / response to salt stress: SOS2 is required for salt tolerance; the SOS pathway is a conserved mechanism for cytosolic Na(^+) detoxification. Recent work positions SOS2 centrally in salt-stress survival modules, including in specific root regions through GSO1-mediated activation. (chen2023asaltstress‐activated pages 1-2, chen2023asaltstress‐activated pages 16-17)

Cellular sodium ion homeostasis and sodium ion export: SOS2 activation of SOS1 directly promotes Na(^+) efflux across the plasma membrane, supporting annotations related to cellular Na(^+) homeostasis and Na(^+) export. (li2023phosphatidicacid–regulatedsos2 pages 1-3, das2010expressionalanalysisand pages 6-7)

Recent developments expanding biological-process understanding (2023)

Root meristem / stem cell niche protection under salinity: The GSO1–SOS2–SOS1 module is reported to protect the Arabidopsis root stem cell niche by enhancing Na(^+) extrusion, providing a spatially specific process-level refinement for SOS2 function in planta. (chen2023asaltstress‐activated pages 1-2, chen2023asaltstress‐activated pages 15-16)

Na(^+)/K(^+) homeostasis coupling via lipid signaling: PA-bound SOS2 promotes Na(^+) efflux through SOS1 and also promotes SOS2 phosphorylation of SCaBP8, attenuating SCaBP8-mediated inhibition of the K(^+) channel AKT1, linking SOS2 to maintenance of Na(^+)/K(^+) balance under salt stress. (li2023phosphatidicacid–regulatedsos2 pages 1-3, li2023phosphatidicacid–regulatedsos2 pages 9-10, li2023phosphatidicacid–regulatedsos2 media e37665a8)

Lower-confidence / context-dependent processes

Tonoplast/vacuolar antiport regulation and Ca(^{2+}) homeostasis: SOS2 has been reported to affect tonoplast Na(^+)/H(^+) antiport activity and to activate CAX1 in heterologous yeast assays, suggesting broader ion-homeostasis roles; however, these are less direct than SOS1 activation and include heterologous evidence, so they may be more appropriate as secondary or context-specific annotations unless corroborated by in planta phosphosite/functional evidence. (gong2004thesos3family pages 4-5, knutova2008functionalcharacterizationof pages 17-20)

Cellular localization and complexes

Best-supported active-site localization

Plasma membrane-associated signaling complex (CBL–SOS2–SOS1): Multiple sources support that SOS2 is recruited to the plasma membrane by CBL partners (e.g., SOS3/CBL4, SCaBP8/CBL10) and, in recent work, that PA promotes SOS2 plasma membrane accumulation and activity. The functional consequence is phosphorylation/activation of SOS1 at the plasma membrane to drive Na(^+) efflux. (li2023phosphatidicacid–regulatedsos2 pages 4-6, chen2023asaltstress‐activated pages 2-3, li2023phosphatidicacid–regulatedsos2 media e37665a8)

Key complexes/partners (strong evidence):
- SOS2–SOS3/CBL4 complex regulating SOS1. (gong2004thesos3family pages 1-2, gong2004thesos3family pages 4-5)
- SOS2–SCaBP8/CBL10 complex, including SCaBP8 phosphorylation by SOS2. (li2023phosphatidicacid–regulatedsos2 pages 1-3, kudla2010calciumsignalsthe pages 11-12)
- GSO1–SOS2 interaction at the plasma membrane and activation by Thr16 phosphorylation. (chen2023asaltstress‐activated pages 2-3)

Baseline localization when expressed alone

Broader CIPK literature indicates CIPKs often display cytoplasmic and nucleoplasmic localization as GFP fusions, and localization of functional complexes is strongly dictated by the CBL partner. This supports conservative CC annotation for SOS2 as cytosolic, with membrane localization/association being complex- and context-dependent. (kudla2010calciumsignalsthe pages 11-12)

Tonoplast/vacuolar context

Evidence suggests SOS2 can regulate tonoplast-associated transport activities (e.g., effects on vacuolar antiport activity and CAX1 activation in yeast), and reviews discuss CBL10–CIPK24 modules with tonoplast localization in salt responses. This should be treated as context-dependent and not as the sole/primary localization of SOS2 across tissues/conditions. (gong2004thesos3family pages 4-5, hunpatin2023therolesof pages 4-6, pardo2010biotechnologyofwater pages 7-9)

Current applications and real-world implementations

CIPK24/SOS2 and the SOS pathway are widely used as engineering targets in plant salt tolerance, including pathway reconstitution in yeast as a functional assay platform for ion-homeostasis modules and as a conceptual basis for biotechnology approaches to salinity stress tolerance. While the retrieved evidence set emphasizes mechanistic and physiological function rather than field deployment metrics, the SOS pathway’s reconstitution and use in stress-tolerance biotechnology is explicitly discussed in biotechnology-focused review literature. (pardo2010biotechnologyofwater pages 12-12)

Annotation-risk assessment (GO review guidance)

  1. Serine/threonine protein kinase activity (SOS2 catalytic role; SnRK3/CIPK family). (gong2004thesos3family pages 3-4, gong2004thesos3family pages 1-2)
  2. Protein phosphorylation specifically tied to SOS1 activation (Na(^+)/H(^+) antiporter regulation) as the most direct substrate-supported function. (gong2004thesos3family pages 3-4, li2023phosphatidicacid–regulatedsos2 pages 1-3)
  3. Response to salt stress / salt tolerance, cellular sodium ion homeostasis, and sodium ion export via SOS1. (chen2023asaltstress‐activated pages 1-2, das2010expressionalanalysisand pages 6-7)
  4. Plasma membrane-associated signaling complex annotations should be framed as conditional/complex-dependent localization (recruited by CBLs and PA), not as an intrinsic transmembrane protein. (li2023phosphatidicacid–regulatedsos2 pages 4-6, li2023phosphatidicacid–regulatedsos2 media e37665a8)

Context-specific / potentially over-extended annotations (use caution)

Explicit negatives / out-of-scope processes

Across the retrieved and scanned sources, there is no evidence supporting annotations for CIPK24/SOS2 in apoptosis, developmental cell death, neuronal function, inflammatory signaling, pyroptosis, synaptic remodeling, or proteolytic maturation/processing. (kudla2010calciumsignalsthe pages 11-12, li2023phosphatidicacid–regulatedsos2 pages 1-3, knutova2008functionalcharacterizationof pages 14-17)

Evidence-to-GO mapping table

GO aspect Suggested annotation term (plain English) Evidence summary (1-2 lines) Key mechanistic details Organism/context Citation IDs
MF Serine/threonine protein kinase activity CIPK24/SOS2 is consistently described as a SnRK3/CIPK Ser/Thr kinase with autophosphorylation and substrate phosphorylation activity; activation-loop phosphomimic mutations constitutively activate the kinase. Thr168 in activation loop; intramolecular autophosphorylation; Mn2+ preferred over Mg2+ in assays; kinase catalytic N-terminus plus regulatory C-terminus Arabidopsis; in vitro kinase assays; foundational biochemical characterization (gong2004thesos3family pages 3-4, gong2004thesos3family pages 2-3, gong2004thesos3family pages 1-2)
MF Protein serine/threonine kinase regulator of SOS1 Na+/H+ antiporter SOS2 phosphorylates and activates SOS1, the plasma-membrane Na+/H+ exchanger, establishing the strongest direct substrate-supported molecular role. Substrate SOS1; activation via CBL4/SOS3 or SCaBP8/CBL10 complexes; Thr16 phosphorylation by GSO1 further activates SOS2 Arabidopsis; salt stress; yeast and in planta reconstitution (chen2023asaltstress‐activated pages 2-3, chen2023asaltstress‐activated pages 1-2, li2023phosphatidicacid–regulatedsos2 pages 1-3)
MF Protein binding to CBL calcium sensors via NAF/FISL motif SOS2 binds CBL/SCaBP calcium sensors through the conserved NAF/FISL motif; this interaction relieves autoinhibition and enables signaling complex formation. NAF/FISL autoinhibitory motif; CBL4/SOS3, CBL10/SCaBP8 binding; PPI motif distinct from CBL-binding region Arabidopsis; Ca2+-dependent activation model (gong2004thesos3family pages 2-3, gong2004thesos3family pages 3-4, hunpatin2023therolesof pages 4-6, knutova2008functionalcharacterizationof pages 14-17)
MF Phosphatidic acid binding Recent evidence shows PA directly binds SOS2 and promotes kinase activity and plasma-membrane accumulation, adding a lipid-regulated facet to SOS2 function. Lys57 required for PA binding; K57G reduces PA binding, PM localization, and activity Arabidopsis; salt stress; lipid-binding assays and complementation (li2023phosphatidicacid–regulatedsos2 pages 1-3, li2023phosphatidicacid–regulatedsos2 pages 9-10, li2023phosphatidicacid–regulatedsos2 media e37665a8)
MF Phosphorylation of SCaBP8/CBL10 SOS2 phosphorylates SCaBP8/CBL10 and this modulates ion-homeostasis signaling; review-level evidence also notes specific phosphorylation of CBL10 Ser-237. Substrate SCaBP8/CBL10; Ser-237 on CBL10; phosphorylation stabilizes or modulates complex behavior Arabidopsis; salt stress; membrane-associated signaling (pardo2010biotechnologyofwater pages 7-9, li2023phosphatidicacid–regulatedsos2 pages 1-3, kudla2010calciumsignalsthe pages 11-12)
MF Protein phosphatase 2C binding SOS2 interacts with PP2Cs, especially ABI2, through its PPI motif, supporting regulatory complex formation rather than core catalysis. ABI2/ABI1 binding; PPI motif; phosphatase-mediated dephosphorylation/off-switch model Arabidopsis; stress signaling regulation (hunpatin2023therolesof pages 4-6, gong2004thesos3family pages 4-5, knutova2008functionalcharacterizationof pages 14-17)
BP Salt tolerance / response to salt stress Loss-of-function and complementation studies support SOS2 as a central positive regulator of salt tolerance in Arabidopsis. Canonical SOS pathway component; activated by CBLs and GSO1; regulates Na+ export systems Arabidopsis; whole-plant salt stress phenotypes (chen2023asaltstress‐activated pages 16-17, knutova2008functionalcharacterizationof pages 17-20, chen2023asaltstress‐activated pages 1-2, pardo2010biotechnologyofwater pages 12-12)
BP Cellular sodium ion homeostasis Strong evidence supports SOS2 as a controller of cytosolic Na+ detoxification through SOS1 activation and associated SOS modules. SOS1 activation; Na+ extrusion; Thr16-GSO1 input; CBL4/SOS3 and CBL10/SCaBP8 modules Arabidopsis; root and shoot salt response (chen2023asaltstress‐activated pages 1-2, hunpatin2023therolesof pages 4-6, pardo2010biotechnologyofwater pages 7-9)
BP Sodium ion export from cell The best-supported process-level role is promotion of Na+ efflux through the plasma membrane via SOS1. Plasma-membrane Na+/H+ antiporter SOS1 as direct downstream effector Arabidopsis; salt stress; yeast and in planta (li2023phosphatidicacid–regulatedsos2 pages 1-3, chen2023asaltstress‐activated pages 1-2, das2010expressionalanalysisand pages 6-7)
BP Potassium ion homeostasis under salt stress Recent work supports a role for SOS2 in Na+/K+ balance by phosphorylating SCaBP8 and relieving inhibition of AKT1-dependent K+ uptake. PA-SOS2-SCaBP8-AKT1 module; Lys57-dependent PA regulation Arabidopsis; salt stress; tissue K+ content and efflux assays (li2023phosphatidicacid–regulatedsos2 pages 1-3, li2023phosphatidicacid–regulatedsos2 pages 9-10, li2023phosphatidicacid–regulatedsos2 media e37665a8)
BP Root stem cell niche protection during salt stress A 2023 EMBO study adds a spatially specific role for SOS2 in protecting the root meristem by enhancing Na+ extrusion. GSO1-SOS2-SOS1 module; Thr16 phosphorylation; meristem/endodermis salt-protection context Arabidopsis root meristem under salinity (chen2023asaltstress‐activated pages 2-3, chen2023asaltstress‐activated pages 16-17, chen2023asaltstress‐activated pages 1-2, chen2023asaltstress‐activated pages 15-16)
BP Vacuolar ion sequestration / vacuolar transport regulation Evidence suggests SOS2 can regulate tonoplast transport processes, but direct in planta assignment is weaker and more context-dependent than plasma-membrane SOS1 activation. CAX1 activation in yeast; tonoplast Na+/H+ antiport and V-ATPase-related regulation; often CBL10-associated Yeast heterologous assays and Arabidopsis tonoplast-related studies (gong2004thesos3family pages 4-5, knutova2008functionalcharacterizationof pages 17-20, hunpatin2023therolesof pages 4-6, pardo2010biotechnologyofwater pages 7-9)
CC Cytoplasm / cytosol SOS2 alone is generally cytoplasmic (and in broader CIPK reviews, often nucleoplasmic), but active localization is strongly partner-dependent. Soluble kinase prior to recruitment; localization shifts with CBL partner or PA Arabidopsis; GFP-fusion/review-level localization evidence (kudla2010calciumsignalsthe pages 11-12, li2023phosphatidicacid–regulatedsos2 pages 1-3)
CC Plasma membrane-associated signaling complex The strongest active-site localization is at the plasma membrane in complexes with CBL4/SOS3 or SCaBP8/CBL10, where SOS2 activates SOS1. CBL lipidation recruits complex; PA promotes PM localization; SOS1 effector at PM Arabidopsis roots/shoots under salt stress (chen2023asaltstress‐activated pages 2-3, hunpatin2023therolesof pages 4-6, li2023phosphatidicacid–regulatedsos2 pages 4-6, batistic2008dualfattyacyl pages 2-3, li2023phosphatidicacid–regulatedsos2 media e37665a8)
CC Tonoplast-associated complex Tonoplast localization is plausible for specific CBL10-CIPK24 contexts, but should be treated as context-specific rather than universal for SOS2. CBL10/SCaBP8 partner specificity; proposed vacuolar Na+ sequestration roles Arabidopsis shoots; salt stress; context-dependent (hunpatin2023therolesof pages 4-6, pardo2010biotechnologyofwater pages 7-9)
CC Nucleus / nucleoplasm General CIPK literature notes many CIPKs can be cytoplasmic and nucleoplasmic when expressed alone, but direct CIPK24-specific nuclear function evidence is limited. No strong CIPK24-specific nuclear mechanism here; likely avoid strong nucleus annotation without direct assay Broad CIPK localization context, not a core active-site claim for SOS2 (kudla2010calciumsignalsthe pages 11-12)

Table: This table maps experimentally supported findings for Arabidopsis CIPK24/SOS2 to candidate GO molecular function, biological process, and cellular component annotations. It highlights high-confidence core annotations versus more context-dependent roles and localizations.

Relevant statistics and data points from recent studies (2023)

Key literature (prioritizing 2023–2024)

  1. Li et al. (Feb 2023). Phosphatidic acid–regulated SOS2 controls sodium and potassium homeostasis in Arabidopsis under salt stress. The EMBO Journal. DOI: https://doi.org/10.15252/embj.2022112401 (li2023phosphatidicacid–regulatedsos2 pages 1-3, li2023phosphatidicacid–regulatedsos2 pages 9-10, li2023phosphatidicacid–regulatedsos2 media e37665a8)
  2. Chen et al. (May 2023). A salt stress-activated GSO1-SOS2-SOS1 module protects the Arabidopsis root stem cell niche by enhancing sodium ion extrusion. The EMBO Journal. DOI: https://doi.org/10.15252/embj.2022113004 (chen2023asaltstress‐activated pages 2-3, chen2023asaltstress‐activated pages 1-2, chen2023asaltstress‐activated pages 15-16)
  3. Hunpatin et al. (Nov 2023). The Roles of Calcineurin B-like Proteins in Plants under Salt Stress. International Journal of Molecular Sciences. DOI: https://doi.org/10.3390/ijms242316958 (hunpatin2023therolesof pages 4-6)

Foundational / high-authority background

  1. Gong et al. (Mar 2004). The SOS3 Family of Calcium Sensors and SOS2 Family of Protein Kinases in Arabidopsis. Plant Physiology. DOI: https://doi.org/10.1104/pp.103.037440 (gong2004thesos3family pages 3-4, gong2004thesos3family pages 1-2, gong2004thesos3family pages 4-5)
  2. Kudla et al. (Mar 2010). Calcium Signals: The Lead Currency of Plant Information Processing. The Plant Cell. DOI: https://doi.org/10.1105/tpc.109.072686 (kudla2010calciumsignalsthe pages 11-12)
  3. Pardo (Apr 2010). Biotechnology of water and salinity stress tolerance. Current Opinion in Biotechnology. DOI: https://doi.org/10.1016/j.copbio.2010.02.005 (pardo2010biotechnologyofwater pages 7-9)

Notes on evidence limitations

This report is constrained to the retrieved full-text excerpts. Some widely cited primary studies (e.g., early PNAS papers on SOS2–SOS3 interaction) were not fully obtainable in this run, so residue-level phosphosite mapping on SOS1 and detailed quantitative phenotypes (Na(^+) flux values, Na(^+)/K(^+) ratios, survival percentages) are summarized from accessible evidence rather than exhaustively enumerated.

References

  1. (gong2004thesos3family pages 3-4): Deming Gong, Yan Guo, Karen S. Schumaker, and Jian-Kang Zhu. The sos3 family of calcium sensors and sos2 family of protein kinases in arabidopsis1. Plant Physiology, 134:919-926, Mar 2004. URL: https://doi.org/10.1104/pp.103.037440, doi:10.1104/pp.103.037440. This article has 292 citations and is from a highest quality peer-reviewed journal.

  2. (gong2004thesos3family pages 1-2): Deming Gong, Yan Guo, Karen S. Schumaker, and Jian-Kang Zhu. The sos3 family of calcium sensors and sos2 family of protein kinases in arabidopsis1. Plant Physiology, 134:919-926, Mar 2004. URL: https://doi.org/10.1104/pp.103.037440, doi:10.1104/pp.103.037440. This article has 292 citations and is from a highest quality peer-reviewed journal.

  3. (li2023phosphatidicacid–regulatedsos2 pages 1-3): Jianfang Li, Like Shen, Xiuli Han, Gefeng He, Wenxia Fan, Yu Li, Shiping Yang, Ziding Zhang, Yongqing Yang, Weiwei Jin, Yi Wang, Wenhua Zhang, and Yan Guo. Phosphatidic acid–regulated sos2 controls sodium and potassium homeostasis in arabidopsis under salt stress. The EMBO Journal, Feb 2023. URL: https://doi.org/10.15252/embj.2022112401, doi:10.15252/embj.2022112401. This article has 102 citations.

  4. (chen2023asaltstress‐activated pages 1-2): Changxi Chen, Gefeng He, Jianfang Li, Javier Perez‐Hormaeche, Tobias Becker, Manqing Luo, Lukas Wallrad, Junping Gao, Jia Li, José M Pardo, Jörg Kudla, and Yan Guo. A salt stress‐activated gso1‐sos2‐sos1 module protects the arabidopsis root stem cell niche by enhancing sodium ion extrusion. The EMBO Journal, May 2023. URL: https://doi.org/10.15252/embj.2022113004, doi:10.15252/embj.2022113004. This article has 71 citations.

  5. (chen2023asaltstress‐activated pages 2-3): Changxi Chen, Gefeng He, Jianfang Li, Javier Perez‐Hormaeche, Tobias Becker, Manqing Luo, Lukas Wallrad, Junping Gao, Jia Li, José M Pardo, Jörg Kudla, and Yan Guo. A salt stress‐activated gso1‐sos2‐sos1 module protects the arabidopsis root stem cell niche by enhancing sodium ion extrusion. The EMBO Journal, May 2023. URL: https://doi.org/10.15252/embj.2022113004, doi:10.15252/embj.2022113004. This article has 71 citations.

  6. (li2023phosphatidicacid–regulatedsos2 media e37665a8): Jianfang Li, Like Shen, Xiuli Han, Gefeng He, Wenxia Fan, Yu Li, Shiping Yang, Ziding Zhang, Yongqing Yang, Weiwei Jin, Yi Wang, Wenhua Zhang, and Yan Guo. Phosphatidic acid–regulated sos2 controls sodium and potassium homeostasis in arabidopsis under salt stress. The EMBO Journal, Feb 2023. URL: https://doi.org/10.15252/embj.2022112401, doi:10.15252/embj.2022112401. This article has 102 citations.

  7. (kudla2010calciumsignalsthe pages 11-12): Jörg Kudla, Oliver Batistič, and Kenji Hashimoto. Calcium signals: the lead currency of plant information processing. Plant Cell, 22:541-563, Mar 2010. URL: https://doi.org/10.1105/tpc.109.072686, doi:10.1105/tpc.109.072686. This article has 1276 citations and is from a highest quality peer-reviewed journal.

  8. (li2023phosphatidicacid–regulatedsos2 pages 4-6): Jianfang Li, Like Shen, Xiuli Han, Gefeng He, Wenxia Fan, Yu Li, Shiping Yang, Ziding Zhang, Yongqing Yang, Weiwei Jin, Yi Wang, Wenhua Zhang, and Yan Guo. Phosphatidic acid–regulated sos2 controls sodium and potassium homeostasis in arabidopsis under salt stress. The EMBO Journal, Feb 2023. URL: https://doi.org/10.15252/embj.2022112401, doi:10.15252/embj.2022112401. This article has 102 citations.

  9. (knutova2008functionalcharacterizationof pages 14-17): I Knutova. Functional characterization of the ca2+-regulated protein kinase atcipk8 involved in aba and oxidative stress responses. Unknown journal, 2008.

  10. (gong2004thesos3family pages 2-3): Deming Gong, Yan Guo, Karen S. Schumaker, and Jian-Kang Zhu. The sos3 family of calcium sensors and sos2 family of protein kinases in arabidopsis1. Plant Physiology, 134:919-926, Mar 2004. URL: https://doi.org/10.1104/pp.103.037440, doi:10.1104/pp.103.037440. This article has 292 citations and is from a highest quality peer-reviewed journal.

  11. (gong2004thesos3family pages 4-5): Deming Gong, Yan Guo, Karen S. Schumaker, and Jian-Kang Zhu. The sos3 family of calcium sensors and sos2 family of protein kinases in arabidopsis1. Plant Physiology, 134:919-926, Mar 2004. URL: https://doi.org/10.1104/pp.103.037440, doi:10.1104/pp.103.037440. This article has 292 citations and is from a highest quality peer-reviewed journal.

  12. (pardo2010biotechnologyofwater pages 7-9): Jose M Pardo. Biotechnology of water and salinity stress tolerance. Current opinion in biotechnology, 21 2:185-96, Apr 2010. URL: https://doi.org/10.1016/j.copbio.2010.02.005, doi:10.1016/j.copbio.2010.02.005. This article has 298 citations and is from a peer-reviewed journal.

  13. (li2023phosphatidicacid–regulatedsos2 pages 9-10): Jianfang Li, Like Shen, Xiuli Han, Gefeng He, Wenxia Fan, Yu Li, Shiping Yang, Ziding Zhang, Yongqing Yang, Weiwei Jin, Yi Wang, Wenhua Zhang, and Yan Guo. Phosphatidic acid–regulated sos2 controls sodium and potassium homeostasis in arabidopsis under salt stress. The EMBO Journal, Feb 2023. URL: https://doi.org/10.15252/embj.2022112401, doi:10.15252/embj.2022112401. This article has 102 citations.

  14. (chen2023asaltstress‐activated pages 16-17): Changxi Chen, Gefeng He, Jianfang Li, Javier Perez‐Hormaeche, Tobias Becker, Manqing Luo, Lukas Wallrad, Junping Gao, Jia Li, José M Pardo, Jörg Kudla, and Yan Guo. A salt stress‐activated gso1‐sos2‐sos1 module protects the arabidopsis root stem cell niche by enhancing sodium ion extrusion. The EMBO Journal, May 2023. URL: https://doi.org/10.15252/embj.2022113004, doi:10.15252/embj.2022113004. This article has 71 citations.

  15. (das2010expressionalanalysisand pages 6-7): Ritika Das and Girdhar Pandey. Expressional analysis and role of calcium regulated kinases in abiotic stress signaling. Current Genomics, 11:2-13, Mar 2010. URL: https://doi.org/10.2174/138920210790217981, doi:10.2174/138920210790217981. This article has 168 citations and is from a peer-reviewed journal.

  16. (chen2023asaltstress‐activated pages 15-16): Changxi Chen, Gefeng He, Jianfang Li, Javier Perez‐Hormaeche, Tobias Becker, Manqing Luo, Lukas Wallrad, Junping Gao, Jia Li, José M Pardo, Jörg Kudla, and Yan Guo. A salt stress‐activated gso1‐sos2‐sos1 module protects the arabidopsis root stem cell niche by enhancing sodium ion extrusion. The EMBO Journal, May 2023. URL: https://doi.org/10.15252/embj.2022113004, doi:10.15252/embj.2022113004. This article has 71 citations.

  17. (knutova2008functionalcharacterizationof pages 17-20): I Knutova. Functional characterization of the ca2+-regulated protein kinase atcipk8 involved in aba and oxidative stress responses. Unknown journal, 2008.

  18. (hunpatin2023therolesof pages 4-6): Oluwaseyi Setonji Hunpatin, Guang Yuan, Tongjia Nong, Chuhan Shi, Xue Wu, Haobao Liu, Yang Ning, and Qian Wang. The roles of calcineurin b-like proteins in plants under salt stress. International Journal of Molecular Sciences, 24:16958, Nov 2023. URL: https://doi.org/10.3390/ijms242316958, doi:10.3390/ijms242316958. This article has 14 citations.

  19. (pardo2010biotechnologyofwater pages 12-12): Jose M Pardo. Biotechnology of water and salinity stress tolerance. Current opinion in biotechnology, 21 2:185-96, Apr 2010. URL: https://doi.org/10.1016/j.copbio.2010.02.005, doi:10.1016/j.copbio.2010.02.005. This article has 298 citations and is from a peer-reviewed journal.

  20. (batistic2008dualfattyacyl pages 2-3): Oliver Batistič, Nadav Sorek, Stefanie Schültke, Shaul Yalovsky, and Jörg Kudla. Dual fatty acyl modification determines the localization and plasma membrane targeting of cbl/cipk ca2+ signaling complexes in arabidopsis. The Plant Cell, 20(5):1346-1362, May 2008. URL: https://doi.org/10.1105/tpc.108.058123, doi:10.1105/tpc.108.058123. This article has 372 citations.