FLS2

Existing Annotations Review

GO Term	Evidence	Action	Reason
GO:0006898 receptor-mediated endocytosis	IDA PMID:23085733 Spatio-temporal cellular dynamics of the Arabidopsis flagell...	KEEP AS NON CORE	Summary: FLS2 is ligand-dependently internalized after flg22 perception, and activation-state-dependent endosomal sorting is well supported. This describes receptor trafficking and signal attenuation rather than the core receptor activity itself. Reason: The annotation is biologically correct for activated FLS2, but it is a regulated fate of the receptor rather than the main evolved molecular function of the gene product. Supporting Evidence: PMID:23085733 FLS2 localizes to bona fide endosomes via two distinct endocytic trafficking routes depending on its activation status.
GO:0016045 detection of bacterium	IMP PMID:10911994 FLS2: an LRR receptor-like kinase involved in the perception...	ACCEPT	Summary: FLS2 was identified genetically as the receptor-like kinase required for Arabidopsis perception of the bacterial flagellin elicitor. Reason: Detection of bacterial flagellin is central to Q9FL28/FLS2 biology and is supported by mutant and complementation evidence in the original FLS2 study. Supporting Evidence: PMID:10911994 The FLS2 gene is ubiquitously expressed and encodes a putative receptor kinase.
GO:0042742 defense response to bacterium	IMP PMID:18158241 Pseudomonas syringae effector AvrPto blocks innate immunity ...	ACCEPT	Summary: FLS2-dependent PAMP perception contributes to antibacterial defense, and AvrPto suppresses this immunity by targeting receptor kinases including FLS2. Reason: Antibacterial defense is a central evolved role of the flagellin receptor, not a peripheral phenotype. FLS2 executes the recognition and receptor-signaling step within this process (PMID:18158241; PMID:23085733). Supporting Evidence: PMID:18158241 AvrPto binds receptor kinases, including Arabidopsis FLS2 and EFR and tomato LeFLS2, to block plant immune responses in the plant cell.
GO:0042742 defense response to bacterium	IMP PMID:19095898 Glucosinolate metabolites required for an Arabidopsis innate...	ACCEPT	Summary: The paper analyzes flg22-triggered innate immune responses including pathogen-triggered callose and resistance outputs. FLS2 acts upstream of these antibacterial defense responses through flagellin perception. Reason: Antibacterial defense is a central evolved role of the flagellin receptor, not a peripheral phenotype. FLS2 executes the recognition and receptor-signaling step within this process (PMID:18158241; PMID:23085733). Supporting Evidence: PMID:19095898 In our seedling growth assay, the Flg22 receptor mutant fls2-c and the IGS biosynthetic mutant ein2-1 are very susceptible
GO:0052544 defense response by callose deposition in cell wall	IMP PMID:19095898 Glucosinolate metabolites required for an Arabidopsis innate...	KEEP AS NON CORE	Summary: Flg22-triggered callose deposition is a downstream PAMP-triggered immunity output requiring the FLS2 pathway. Reason: Full text directly reports loss of flg22-induced callose in fls2 mutants. Retain this specific downstream output as non-core: FLS2 supplies receptor signaling rather than callose-synthase catalysis. Supporting Evidence: PMID:19095898 Mutants lacking the functional Flg22 receptor encoded by the FLS2 gene (11) or the functional callose synthase encoded by the PMR4 gene (12) did not respond to Flg22 treatment
GO:0140426 pathogen-associated molecular pattern receptor signaling pathway	IMP PMID:20113440 Early signaling through the Arabidopsis pattern recognition ...	ACCEPT	Summary: FLS2-dependent flg22 perception activates early plasma-membrane electrical and calcium-associated signaling through the PAMP receptor pathway. Reason: This is the best existing biological-process term for the core FLS2 role: a cell-surface receptor pathway initiated by bacterial flagellin perception. Supporting Evidence: PMID:20113440 activation of FLS2 and EFR lead to BAK1-dependent, calcium-associated plasma membrane anion channel opening as an initial step in the pathogen defense pathway.
GO:0004672 protein kinase activity	IEA GO_REF:0000002	MODIFY	Summary: The InterPro kinase-domain mapping is correct but too generic for FLS2, which is a single-pass receptor-like serine/threonine kinase. Reason: A more specific experimentally and domain-supported term exists for this protein. Proposed replacements: transmembrane receptor protein serine/threonine kinase activity
GO:0004674 protein serine/threonine kinase activity	IEA GO_REF:0000003	MODIFY	Summary: FLS2 has serine/threonine protein kinase activity, but the EC-based term omits the receptor and transmembrane context that distinguishes this protein. Reason: The specific receptor protein serine/threonine kinase term is a better fit for an LRR receptor-like kinase. Proposed replacements: transmembrane receptor protein serine/threonine kinase activity
GO:0004675 transmembrane receptor protein serine/threonine kinase activity	ISS PMID:10911994 FLS2: an LRR receptor-like kinase involved in the perception...	ACCEPT	Summary: FLS2 encodes a membrane-spanning LRR receptor-like kinase whose cytoplasmic kinase domain is required for flagellin responses. Reason: This molecular-function term captures the core receptor kinase activity of Q9FL28/FLS2. Supporting Evidence: PMID:10911994 The FLS2 gene is ubiquitously expressed and encodes a putative receptor kinase.
GO:0005515 protein binding	IPI DOI:10.1038/s41586-020-2210-3	REMOVE	Summary: The cited work supports FLS2-BAK1/BIK1 receptor complex context and BIK1 release/internalization, but "protein binding" is too vague to represent the functional role of FLS2. Reason: The interaction evidence is useful mechanistic context, but GO:0005515 does not convey FLS2's receptor kinase or PAMP receptor activity. Remove the uninformative generic MF annotation while retaining the reported interaction as mechanistic evidence; this decision does not deny that the association occurs. The cited association does not establish a distinct, more informative molecular activity for this row. Supporting Evidence: PMID:32404997 the RLCK BOTRYTIS-INDUCED KINASE 1 (BIK1) is monoubiquitinated following phosphorylation, then released from the flagellin receptor FLAGELLIN SENSING 2 (FLS2)-BRASSINOSTEROID INSENSITIVE 1-ASSOCIATED KINASE 1 (BAK1) complex
GO:0005515 protein binding	IPI PMID:17625569 A flagellin-induced complex of the receptor FLS2 and BAK1 in...	REMOVE	Summary: The publication shows ligand-dependent FLS2 association with BAK1 during flagellin signaling. Reason: A generic protein binding annotation obscures the specific coreceptor complex formed during PAMP receptor signaling. Remove the uninformative generic MF annotation while retaining the reported interaction as mechanistic evidence; this decision does not deny that the association occurs. The cited association does not establish a distinct, more informative molecular activity for this row. Supporting Evidence: PMID:17625569 We provide evidence that FLS2 and BAK1 form a complex in vivo, in a specific ligand-dependent manner, within the first minutes of stimulation with flagellin.
GO:0005515 protein binding	IPI PMID:17626179 The receptor-like kinase SERK3/BAK1 is a central regulator o...	REMOVE	Summary: SERK3/BAK1 rapidly enters an elicitor-dependent complex with FLS2 during flg22-triggered PTI. Reason: The physical interaction is real, but the annotation should not elevate vague protein binding over the specific FLS2-BAK1 receptor signaling event. Remove the uninformative generic MF annotation while retaining the reported interaction as mechanistic evidence; this decision does not deny that the association occurs. The cited association does not establish a distinct, more informative molecular activity for this row. Supporting Evidence: PMID:17626179 AtSERK3/BAK1 rapidly enters an elicitor-dependent complex with FLAGELLIN SENSING 2 (FLS2)
GO:0005515 protein binding	IPI PMID:18158241 Pseudomonas syringae effector AvrPto blocks innate immunity ...	REMOVE	Summary: AvrPto binds Arabidopsis FLS2 and other receptor kinases to block plant immune responses. Reason: Effector binding is mechanistically relevant but not a core molecular function of the plant receptor; GO:0005515 is too broad to be useful. Remove the uninformative generic MF annotation while retaining the reported interaction as mechanistic evidence; this decision does not deny that the association occurs. The cited association does not establish a distinct, more informative molecular activity for this row. Supporting Evidence: PMID:18158241 AvrPto binds receptor kinases, including Arabidopsis FLS2 and EFR and tomato LeFLS2, to block plant immune responses in the plant cell.
GO:0005515 protein binding	IPI PMID:19062288 Plant pattern-recognition receptor FLS2 is directed for degr...	REMOVE	Summary: AvrPtoB associates with FLS2 and promotes ubiquitination/degradation of the receptor as a pathogen virulence mechanism. Reason: This pathogen effector interaction is not the core FLS2 function and is better discussed as immune suppression/turnover context than as generic protein binding. Remove the uninformative generic MF annotation while retaining the reported interaction as mechanistic evidence; this decision does not deny that the association occurs. The cited association does not establish a distinct, more informative molecular activity for this row. Supporting Evidence: PMID:19062288 We show that AvrPtoB, through its N terminus, associates with FLS2 and BAK1, of which interaction with FLS2 is enhanced by flg22 activation.
GO:0005515 protein binding	IPI PMID:20018686 A receptor-like cytoplasmic kinase, BIK1, associates with a ...	REMOVE	Summary: BIK1 associates with the FLS2/BAK1 receptor complex and is phosphorylated upon flagellin perception. Reason: The interaction supports the signaling complex, but GO:0005515 is under-informative compared with FLS2's PAMP receptor signaling role. Remove the uninformative generic MF annotation while retaining the reported interaction as mechanistic evidence; this decision does not deny that the association occurs. The cited association does not establish a distinct, more informative molecular activity for this row. Supporting Evidence: PMID:20018686 BIK1 associates with FLS2 and BAK1 in vivo and in vitro.
GO:0005515 protein binding	IPI PMID:20404519 Phosphorylation of receptor-like cytoplasmic kinases by bact...	REMOVE	Summary: The cited report reviews BIK1 and related RLCK association with the flagellin receptor complex downstream of FLS2/BAK1. Reason: This is useful pathway context, but the generic binding term should not be retained as a core functional annotation. Remove the uninformative generic MF annotation while retaining the reported interaction as mechanistic evidence; this decision does not deny that the association occurs. The cited association does not establish a distinct, more informative molecular activity for this row. Supporting Evidence: PMID:20404519 We recently identified a receptor-like cytoplasmic kinase (RLCK) BIK1 that associates with flagellin receptor complex to initiate plant innate immunity.
GO:0005515 protein binding	IPI PMID:20413097 Receptor-like cytoplasmic kinases integrate signaling from m...	REMOVE	Summary: BIK1 and related PBL kinases interact with FLS2 and are rapidly phosphorylated after FLS2 activation. Reason: The evidence supports downstream immune receptor complex signaling, not an informative standalone protein-binding function. Remove the uninformative generic MF annotation while retaining the reported interaction as mechanistic evidence; this decision does not deny that the association occurs. The cited association does not establish a distinct, more informative molecular activity for this row. Supporting Evidence: PMID:20413097 In unstimulated plants, BIK1 and PBL1 interact with FLS2 and are rapidly phosphorylated upon FLS2 activation by its ligand flg22.
GO:0005515 protein binding	IPI PMID:20472560 Novel functions of Stomatal Cytokinesis-Defective 1 (SCD1) i...	REMOVE	Summary: SCD1 was recovered in FLS2-antibody immunoprecipitates from solubilized microsomal membranes independently of flg22 treatment. Reason: Full-text retrieval resolves the interaction-evidence gap: co-immunoprecipitation supports association with FLS2-containing material, without establishing direct binary binding. Generic protein binding remains under-informative for the receptor function. Remove the uninformative generic MF annotation while retaining the reported interaction as mechanistic evidence; this decision does not deny that the association occurs. The cited association does not establish a distinct, more informative molecular activity for this row. Supporting Evidence: PMID:20472560 Here, we used the same approach to identify a protein with an apparent molecular mass of about 140 kDa that immunoprecipitated with the αFLS2 antibody in a PF22-independent manner from solubilized microsomal membranes of La-er cell culture
GO:0005515 protein binding	IPI PMID:21499263 Stem-cell-triggered immunity through CLV3p-FLS2 signalling.	UNDECIDED	Summary: The study reports CLV3p-triggered FLS2 signaling, including receptor-complex association, but the CLV3 immune-ligand interpretation has been challenged experimentally. Reason: The original result should not be presented as established noncanonical ligand specificity. Segonzac et al. (PMID:22923673) failed to reproduce CLV3 activation of immunity; preserve the IPI row pending resolution of the ligand-dependent assay discrepancy. Supporting Evidence: PMID:22923673 FLS2 does not recognize CLV3
GO:0005515 protein binding	IPI PMID:21726371 Physical association of pattern-triggered immunity (PTI) and...	REMOVE	Summary: FLS2 was reported to physically associate with several ETI immune receptors, suggesting early PTI/ETI receptor proximity. Reason: These interactions are not the defining molecular function of FLS2 and GO:0005515 is too nonspecific for curation. Remove the uninformative generic MF annotation while retaining the reported interaction as mechanistic evidence; this decision does not deny that the association occurs. The cited association does not establish a distinct, more informative molecular activity for this row. Supporting Evidence: PMID:21726371 Here, we provide evidence that FLS2 is physically associated with all three R proteins.
GO:0005515 protein binding	IPI PMID:22087006 Brassinosteroids inhibit pathogen-associated molecular patte...	REMOVE	Summary: The study examines FLS2-mediated immune signaling and BAK1-related pathway context during brassinosteroid crosstalk. Reason: Generic protein binding does not capture the specific signaling biology and should not be treated as a core FLS2 annotation. Remove the uninformative generic MF annotation while retaining the reported interaction as mechanistic evidence; this decision does not deny that the association occurs. The cited association does not establish a distinct, more informative molecular activity for this row. Supporting Evidence: PMID:22087006 BAK1 recruited by FLS2 seems to be different from that recruited by BRI1, as BL did not displace the amount of BAK1 immunoprecipitated with FLS2.
GO:0005515 protein binding	IPI PMID:23250427 CRT1 is a nuclear-translocated MORC endonuclease that partic...	REMOVE	Summary: CRT1/MORC1 was reported to interact with FLS2 in immunity-related assays. Reason: This interaction is peripheral regulatory context and is not an informative molecular-function annotation for FLS2. Remove the uninformative generic MF annotation while retaining the reported interaction as mechanistic evidence; this decision does not deny that the association occurs. The cited association does not establish a distinct, more informative molecular activity for this row. Supporting Evidence: PMID:23250427 Consistent with its role in PAMP-triggered immunity, CRT1 interacted with the PAMP recognition receptor FLS2.
GO:0005515 protein binding	IPI PMID:23395902 Pseudomonas HopU1 modulates plant immune receptor levels by ...	REMOVE	Summary: GRP7 physically associates with FLS2 protein as well as binding FLS2 transcripts. HopU1 disrupts RNA binding rather than the GRP7-FLS2 protein association. Reason: The protein interaction is supported, but generic protein binding does not identify the receptor activity. The RNA-regulation mechanism must not be used to deny the separate protein association. Remove the uninformative generic MF annotation while retaining the reported interaction as mechanistic evidence; this decision does not deny that the association occurs. The cited association does not establish a distinct, more informative molecular activity for this row. Supporting Evidence: PMID:23395902 Here, we show that GRP7 associates with translational components, as well as with the pattern recognition receptors FLS2 and EFR.
GO:0005515 protein binding	IPI PMID:23532072 BR-SIGNALING KINASE1 physically associates with FLAGELLIN SE...	REMOVE	Summary: BSK1 physically associates with FLS2 and contributes to a subset of flg22-induced immune responses. Reason: The interaction supports pathway architecture, but generic protein binding is much less informative than receptor kinase/PAMP receptor signaling. Remove the uninformative generic MF annotation while retaining the reported interaction as mechanistic evidence; this decision does not deny that the association occurs. The cited association does not establish a distinct, more informative molecular activity for this row. Supporting Evidence: PMID:23532072 BSK1 physically associates with the PAMP receptor FLAGELLIN SENSING2
GO:0005515 protein binding	IPI PMID:24114786 Structural basis for flg22-induced activation of the Arabido...	MODIFY	Summary: The structural study directly supports flg22 perception by FLS2 and flg22-induced FLS2-BAK1 immune complex assembly. Reason: For this evidence, the more informative molecular-function annotation is pattern recognition receptor activity, rather than generic protein binding. Proposed replacements: pattern recognition receptor activity Supporting Evidence: PMID:24114786 Flagellin perception in Arabidopsis is through recognition of its highly conserved N-terminal epitope (flg22) by flagellin-sensitive 2 (FLS2).
GO:0005515 protein binding	IPI PMID:24629339 The FLS2-associated kinase BIK1 directly phosphorylates the ...	REMOVE	Summary: The paper places RBOHD downstream of the FLS2-associated kinase BIK1 in ROS and stomatal defense signaling. Reason: The evidence supports pathway wiring downstream of FLS2, but GO:0005515 does not describe FLS2's core activity. Remove the uninformative generic MF annotation while retaining the reported interaction as mechanistic evidence; this decision does not deny that the association occurs. The cited association does not establish a distinct, more informative molecular activity for this row. Supporting Evidence: PMID:24629339 the receptor-like cytoplasmic kinase BIK1, a component of the FLS2 immune receptor complex
GO:0005515 protein binding	IPI PMID:27208222 Two Redundant Receptor-Like Cytoplasmic Kinases Function Dow...	REMOVE	Summary: PCRK1 and PCRK2 interact with FLS2 and act downstream of pattern recognition receptors in salicylic-acid biosynthesis activation. Reason: These interactions are useful regulatory context, but they should not be curated as a generic binding function of FLS2. Remove the uninformative generic MF annotation while retaining the reported interaction as mechanistic evidence; this decision does not deny that the association occurs. The cited association does not establish a distinct, more informative molecular activity for this row. Supporting Evidence: PMID:27208222 Both PCRK1 and PCRK2 interact with the pattern recognition receptor FLS2
GO:0005515 protein binding	IPI PMID:27317676 The Arabidopsis Malectin-Like/LRR-RLK IOS1 Is Critical for B...	REMOVE	Summary: IOS1 associates with FLS2/EFR/CERK1 complexes and promotes FLS2-BAK1 complex formation upon MAMP treatment. Reason: IOS1 binding is a pathway-regulatory interaction; the generic GO:0005515 term is not informative for FLS2 core function. Remove the uninformative generic MF annotation while retaining the reported interaction as mechanistic evidence; this decision does not deny that the association occurs. The cited association does not establish a distinct, more informative molecular activity for this row. Supporting Evidence: PMID:27317676 IOS1 also associated with BAK1 in a ligand-independent manner and positively regulated FLS2-BAK1 complex formation upon MAMP treatment.
GO:0005515 protein binding	IPI PMID:29320478 An extracellular network of Arabidopsis leucine-rich repeat ...	REMOVE	Summary: The extracellular LRR-RK network study provides broad high-throughput interaction context for FLS2 and other receptor kinases. Reason: The interaction network is valuable context, but individual generic protein-binding annotations are too nonspecific and should not define FLS2 function. Remove the uninformative generic MF annotation while retaining the reported interaction as mechanistic evidence; this decision does not deny that the association occurs. The cited association does not establish a distinct, more informative molecular activity for this row. Supporting Evidence: PMID:29320478 2nd Rank: FLS2 as an internal control but as well as a self-interaction52
GO:0005515 protein binding	IPI PMID:32327536 STRESS INDUCED FACTOR 2 Regulates Arabidopsis Stomatal Immun...	REMOVE	Summary: SIF2 physically associates with the FLS2-BAK1 PRR complex and links it to SLAC1-dependent stomatal immunity. Reason: This is a specific regulatory interaction in stomatal immunity, but GO:0005515 is too vague for the FLS2 review. Remove the uninformative generic MF annotation while retaining the reported interaction as mechanistic evidence; this decision does not deny that the association occurs. The cited association does not establish a distinct, more informative molecular activity for this row. Supporting Evidence: PMID:32327536 SIF2 physically associates with the FLS2-BAK1 PRR complex
GO:0005524 ATP binding	IEA GO_REF:0000002	KEEP AS NON CORE	Summary: ATP binding is expected for the cytoplasmic protein kinase domain of FLS2. Reason: The annotation is compatible with the kinase domain but is less informative than the receptor protein serine/threonine kinase activity.
GO:0042802 identical protein binding	IPI PMID:29320478 An extracellular network of Arabidopsis leucine-rich repeat ...	KEEP AS NON CORE	Summary: The interaction-network study explicitly includes FLS2 self-interaction among high-confidence extracellular-domain interactions. Reason: Self-association evidence can coexist with ligand-dependent BAK1 heteromerization. Retain this specific interaction as non-core; the heteromeric activation model does not refute self-interaction. Supporting Evidence: PMID:29320478 2nd Rank: FLS2 as an internal control but as well as a self-interaction52
GO:0106310 protein serine kinase activity	IEA GO_REF:0000116	MODIFY	Summary: The serine-phosphorylation mapping is chemically compatible with FLS2, but receptor protein serine/threonine kinase activity better represents its membrane-spanning signaling function. Reason: The Rhea-derived serine kinase annotation is not false. GO:0004675 adds the biologically defining receptor context, consistent with the membrane-spanning LRR kinase architecture, the original FLS2 characterization (PMID:10911994), and the independently annotated receptor-kinase function. The replacement selects a more informative functional description; it does not claim that threonine activity contradicts serine activity or that GO:0004675 is a strict descendant of the serine-only term. Proposed replacements: transmembrane receptor protein serine/threonine kinase activity
GO:0007165 signal transduction	IEA GO_REF:0000117	MODIFY	Summary: FLS2 clearly participates in signal transduction, but this ARBA term is far broader than the known flagellin/PAMP receptor pathway. Reason: The specific FLS2 process is pathogen-associated molecular pattern receptor signaling. Proposed replacements: pathogen-associated molecular pattern receptor signaling pathway
GO:0007178 cell surface receptor protein serine/threonine kinase signaling pathway	IEA GO_REF:0000108	MODIFY	Summary: This logically inferred pathway term is directionally correct but still less specific than FLS2's established role in PAMP receptor signaling. Reason: The PAMP receptor signaling term more accurately represents the flagellin-triggered immune pathway. Proposed replacements: pathogen-associated molecular pattern receptor signaling pathway
GO:0071555 cell wall organization	IEA GO_REF:0000117	MODIFY	Summary: FLS2 acts upstream of callose deposition after flg22 perception, but it is not a general cell wall organization factor. Reason: A defense-specific callose deposition term is more accurate than broad cell wall organization. Proposed replacements: defense response by callose deposition in cell wall
GO:0005768 endosome	IDA DOI:10.1038/s41586-020-2210-3	MODIFY	Summary: Ligand-triggered FLS2/BIK1 pathway studies support dynamic endocytic compartment localization, but FLS2 is a single-pass membrane receptor. Reason: Endosome membrane is the more specific cellular-component term for the membrane-embedded receptor after internalization. Proposed replacements: endosome membrane Supporting Evidence: PMID:32404997 The timing of the ligand-induced increase in BIK1-GFP puncta differed from that of FLS2-GFP, in which puncta numbers were significantly increased 35 min after flg22 treatment
GO:0005768 endosome	IDA PMID:23085733 Spatio-temporal cellular dynamics of the Arabidopsis flagell...	MODIFY	Summary: Activated FLS2 is sorted into endosomal compartments after flg22 treatment. Reason: Because FLS2 is a transmembrane receptor, endosome membrane is more precise than the whole endosome component. Proposed replacements: endosome membrane Supporting Evidence: PMID:23085733 FLS2 localizes to bona fide endosomes via two distinct endocytic trafficking routes depending on its activation status.
GO:0005886 plasma membrane	IDA DOI:10.1038/s41586-020-2210-3	ACCEPT	Summary: FLS2 is a plasma-membrane receptor in the flagellin-triggered PRR complex. Reason: Plasma membrane localization is essential to FLS2's cell-surface PAMP receptor role. Supporting Evidence: PMID:23085733 The plasma membrane receptor flagellin sensing2 (FLS2) confers immunity against bacterial infection through perception of flagellin (flg22).
GO:0005886 plasma membrane	IEA GO_REF:0000044	ACCEPT	Summary: UniProt subcellular-location mapping to plasma membrane is consistent with direct experimental localization and FLS2 receptor biology. Reason: This location is well supported by independent experimental studies and is central to FLS2 function. Supporting Evidence: PMID:23085733 The plasma membrane receptor flagellin sensing2 (FLS2) confers immunity against bacterial infection through perception of flagellin (flg22).
GO:0005886 plasma membrane	ISM GO_REF:0000122	ACCEPT	Summary: Prediction-based plasma membrane localization agrees with the experimentally established cell-surface receptor localization. Reason: Although the evidence code is computational, the asserted location is strongly supported by the overall literature. Supporting Evidence: PMID:23085733 The plasma membrane receptor flagellin sensing2 (FLS2) confers immunity against bacterial infection through perception of flagellin (flg22).
GO:0005886 plasma membrane	HDA PMID:17644812 A high content in lipid-modified peripheral proteins and int...	ACCEPT	Summary: Plasma membrane proteomics identified Arabidopsis plasma membrane proteins, including receptor-like kinases, and is consistent with FLS2's cell-surface localization. Reason: The high-throughput annotation is consistent with direct FLS2 localization studies and the receptor's topology. Supporting Evidence: PMID:23085733 The plasma membrane receptor flagellin sensing2 (FLS2) confers immunity against bacterial infection through perception of flagellin (flg22).
GO:0005886 plasma membrane	EXP PMID:24923602 Salicylic acid signaling controls the maturation and localiz...	ACCEPT	Summary: Salicylic-acid signaling increases the plasma-membrane pool of FLS2 and BAK1, supporting PM localization of the receptor complex. Reason: Plasma membrane localization is experimentally supported and biologically central for FLS2 ligand perception. Supporting Evidence: PMID:23085733 The plasma membrane receptor flagellin sensing2 (FLS2) confers immunity against bacterial infection through perception of flagellin (flg22).
GO:0005886 plasma membrane	EXP PMID:32404997 Ligand-induced monoubiquitination of BIK1 regulates plant im...	ACCEPT	Summary: FLS2-BAK1 receptor complex studies support plasma membrane localization before ligand-triggered downstream BIK1 release and endocytic dynamics. Reason: This is a core cellular location for FLS2-mediated PAMP perception. Supporting Evidence: PMID:23085733 The plasma membrane receptor flagellin sensing2 (FLS2) confers immunity against bacterial infection through perception of flagellin (flg22).
GO:0010008 endosome membrane	IEA GO_REF:0000044	KEEP AS NON CORE	Summary: UniProt subcellular-location mapping places activated/internalized FLS2 at the endosome membrane. Reason: Endosome membrane localization is a supported trafficking state of FLS2, but the primary site of ligand perception is the plasma membrane.
GO:0010008 endosome membrane	EXP PMID:24923602 Salicylic acid signaling controls the maturation and localiz...	KEEP AS NON CORE	Summary: FLS2 membrane pools and trafficking are regulated in defense-related secretory/endosomal contexts. Reason: Retain established endosomal receptor localization as non-core on independent direct FLS2 trafficking evidence (PMID:23085733). PMID:24923602 chiefly establishes salicylic-acid-regulated plasma-membrane pools; its abstract is not evidence for an endosome membrane. Supporting Evidence: PMID:23085733 FLS2 localizes to bona fide endosomes via two distinct endocytic trafficking routes depending on its activation status.
GO:0010008 endosome membrane	EXP PMID:32404997 Ligand-induced monoubiquitination of BIK1 regulates plant im...	KEEP AS NON CORE	Summary: Ligand-triggered FLS2 complex signaling is coupled to endocytic dynamics of signaling components. Reason: Endosome membrane localization is relevant to receptor/signaling component turnover but is not the primary core location for PAMP perception. Supporting Evidence: PMID:32404997 The timing of the ligand-induced increase in BIK1-GFP puncta differed from that of FLS2-GFP, in which puncta numbers were significantly increased 35 min after flg22 treatment
GO:0012505 endomembrane system	IDA DOI:10.1038/s41586-020-2210-3	MODIFY	Summary: FLS2 pathway components enter endocytic compartments after ligand activation, but "endomembrane system" is too broad for a curated FLS2 location. Reason: Endosome membrane is the more specific and biologically informative term for the activated receptor trafficking state. Proposed replacements: endosome membrane Supporting Evidence: PMID:32404997 The timing of the ligand-induced increase in BIK1-GFP puncta differed from that of FLS2-GFP, in which puncta numbers were significantly increased 35 min after flg22 treatment
GO:0016020 membrane	ISS PMID:10911994 FLS2: an LRR receptor-like kinase involved in the perception...	MODIFY	Summary: FLS2 was identified as a membrane receptor-like kinase, but the generic membrane term is underspecified. Reason: Plasma membrane is the experimentally supported and functionally relevant membrane compartment for flagellin perception. Proposed replacements: plasma membrane Supporting Evidence: PMID:10911994 The FLS2 gene is ubiquitously expressed and encodes a putative receptor kinase. PMID:23085733 The plasma membrane receptor flagellin sensing2 (FLS2) confers immunity against bacterial infection through perception of flagellin (flg22).
GO:0016020 membrane	IDA PMID:16510871 Ligand-induced endocytosis of the pattern recognition recept...	MODIFY	Summary: FLS2-GFP resides at the cell membrane and moves into intracellular vesicles after flg22 stimulation. Reason: The direct localization evidence supports more specific plasma membrane and endosome membrane annotations. Proposed replacements: plasma membrane endosome membrane Supporting Evidence: PMID:16510871 Stimulation with the flagellin epitope flg22 induces its transfer into intracellular mobile vesicles, followed by degradation.
GO:0071944 cell periphery	IEA GO_REF:0000117	MODIFY	Summary: ARBA inferred a broad cell-periphery location that is consistent with FLS2 being a cell-surface receptor. Reason: Plasma membrane is the more precise cellular-component term for FLS2. Proposed replacements: plasma membrane

Gene Description

Existing Annotations Review

Core Functions

FLS2 enables extracellular pattern-recognition receptor activity for bacterial flagellin-derived flg22 at the plant plasma membrane, leading to ligand-induced BAK1/SERK co-receptor recruitment and activation of pattern-triggered immunity.

References

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