Chemokine-mediated signaling pathway module

Secreted chemokines (exemplified by the ELR-positive CXC chemokine CXCL8/IL-8) bind glycosaminoglycans in the extracellular region and engage seven-transmembrane Gi-coupled chemokine receptors (such as CXCR1/CXCR2 for CXCL8 and CCR5 for CC chemokines) at the leukocyte plasma membrane. Agonist binding initiates the chemokine-mediated signaling pathway (GO:0070098) and the specific interleukin-8-mediated signaling pathway (GO:0038112), promoting heterotrimeric Gi nucleotide exchange and Gbetagamma/Galpha_i signaling through PI3Kgamma (PIK3CG), phospholipase C beta calcium mobilization, and RhoA-dependent actomyosin remodeling to direct leukocyte chemotaxis (GO:0060326) and neutrophil chemotaxis (GO:0030593).

MODULE:chemokine_signalingDRAFTSignaling Pathwaymodules/chemokine_signaling.yaml
chemokine-mediated signaling pathwayGO:0070098 interleukin-8-mediated signaling pathwayGO:0038112
file:modules/chemokine_signaling-deep-research-falcon.md
Chemokine-mediated signaling pathway Falcon module review
Falcon/Edison module review generated 2026-06-28 is linked as supporting evidence for module boundaries, core mechanism, variation, constraints, and failure modes; open questions in that report require manual review before promotion to curated knowledge gaps.
GO:0070098
chemokine-mediated signaling pathway
The module is grounded in the GO biological process term for chemokine-mediated signaling pathway (GO:0070098) and its ligand-specific child term interleukin-8-mediated signaling pathway (GO:0038112).
GO:0038112
interleukin-8-mediated signaling pathway
Specific child pathway initiated by CXCL8 (interleukin-8) binding to CXCR1 and CXCR2 on neutrophils and other target cells.
PMID:1840701
Structure and functional expression of a human interleukin-8 receptor.
Establishes high-affinity CXCL8 binding to cloned human CXCR1 and downstream calcium mobilization.
Mammalian cells transfected with the IL-8 receptor cDNA clone bind IL-8 with high affinity and respond specifically to IL-8 by transiently mobilizing calcium.
PMID:32610344
Structural basis of CXC chemokine receptor 2 activation and signalling.
Resolves the active ternary signaling complex of CXCL8, CXCR2, and heterotrimeric Gi.
Here we present the cryo-electron microscopy structures of interleukin-8 (IL-8, also known as CXCL8)-activated human CXC chemokine receptor 2 (CXCR2) in complex with Gi protein, along with a crystal structure of CXCR2 bound to a designed allosteric antagonist.
PMID:37433790
Structural basis of CXC chemokine receptor 1 ligand binding and activation.
Resolves the cryo-EM structure of the active CXCL8-CXCR1-Gi signaling complex.
Here, we solve the structure of CXCR1 complexed with CXCL8 and cognate G-proteins using cryo-EM, showing the detailed interactions between the receptor, the chemokine and Gαi protein.
PANTHER:PTN002564680
PAINT node PTN002564680 for ELR-positive CXC chemokines (CXCL8)
Local PAINT IBD node in PTHR12015 with propagated terms C:GO:0005576, F:GO:0008009, F:GO:0045236, P:GO:0006954, P:GO:0030593, P:GO:0061844, P:GO:0071222; PAINT date 20260828.
PANTHER:PTN001628461
PAINT node PTN001628461 for chemokine receptors (CXCR2, CCR5)
Local PAINT IBD node in PTHR10489 with propagated terms C:GO:0009897, F:GO:0016493, F:GO:0019957, P:GO:0006955, P:GO:0007204, P:GO:0019722, P:GO:0060326; PAINT date 20260828.
PANTHER:PTN002573743
PAINT node PTN002573743 for CXCR2 neutrophil chemotaxis
Local PAINT IBD node in PTHR10489 with propagated terms P:GO:0030593; PAINT date 20200312.
PANTHER:PTN000026392
PAINT node PTN000026392 for G protein alpha subunits (GNAI2)
Local PAINT IBD node in PTHR10218 with propagated terms C:GO:0005737, C:GO:0005834, F:GO:0003925, P:GO:0007188; PAINT date 20260828.
PANTHER:PTN000005673
PAINT node PTN000005673 for PIK3CG
Local PAINT IBD node in PTHR10048 with propagated terms C:GO:0005737, C:GO:0016020, F:GO:0052742, P:GO:0046854; PAINT date 20260528.
PANTHER:PTN000005674
PAINT node PTN000005674 for PIK3CG
Local PAINT IBD node in PTHR10048 with propagated terms C:GO:0005886, F:GO:0016303, F:GO:0035005, P:GO:0043491; PAINT date 20240205.
PANTHER:PTN000632671
PAINT node PTN000632671 for RHOA
Local PAINT IBD node in PTHR24072 with propagated terms C:GO:0005886, F:GO:0003924, F:GO:0005525, P:GO:0007015, P:GO:0007165; PAINT date 20260529.
PANTHER:PTN000799655
PAINT node PTN000799655 for PIK3CG
Local PAINT IBD node in PTHR10048 with propagated terms C:GO:0005942; PAINT date 20240516.
PANTHER:PTN000799659
PAINT node PTN000799659 for PIK3CG
Local PAINT IBD node in PTHR10048 with propagated terms C:GO:0005943, C:GO:0005944, F:GO:0046934; PAINT date 20240918.
PANTHER:PTN001178055
PAINT node PTN001178055 for RHOA
Local PAINT IBD node in PTHR24072 with propagated terms P:GO:0016477; PAINT date 20250903.
PANTHER:PTN002784793
PAINT node PTN002784793 for RHOA
Local PAINT IBD node in PTHR24072 with propagated terms P:GO:0007266, P:GO:0043149; PAINT date 20231109.
PANTHER:PTN008393484
PAINT node PTN008393484 for RHOA
Local PAINT IBD node in PTHR24072 with propagated terms C:GO:0005829, P:GO:0032956; PAINT date 20260529.

Curated signaling-pathway module upgraded from GENE_PRODUCT exemplars to PANTHER FAMILY/subfamily selectors with explicit molecular functions, biological processes, cellular locations, and PAINT/experimental evidence across all participants. The CXCL8-CXCR2 arm models the specific interleukin-8-mediated signaling pathway (GO:0038112) and neutrophil chemotaxis (GO:0030593) within the general chemokine-mediated signaling pathway (GO:0070098). Retained Falcon deep-research citations in references are machine-generated and have not been manually adjudicated against primary literature.

4Nodes
3Parts
0Variant Sets
0Variants
6Annotons
2Connections

Derived QC

Recommended-field compliance

100.0% recommended fields populated

All recommended fields populated.

Module deep research

✓ present

  • chemokine_signaling-deep-research-falcon.md (falcon)

Leaf nodes lacking representative members

✓ every leaf node grounds to a representative protein.

Template conformance

✓ every declared conforms_to bundle matches its template motif.

Function consistency and core coverage

3 gene-function check(s) reflected in core functions · 0 conflict(s) · 8 evidence or coverage gap(s) (12 comparison(s))

Retained noncore functions are reported separately; they do not require promotion to core functions. Support from representative genes does not establish conservation across the whole family. Missing reviews or identifiers leave a claim unverified.

AnnotonParticipantFunctionAssessment
cxcl8_cxcl8_chemokine_ligand CXCL8
UniProtKB:P10145
Family Representative 		chemokine activity
GO:0008009 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
cxcr2_cxcr2_chemokine_receptor CXCR2
UniProtKB:P25025
Family Representative 		C-X-C chemokine receptor activity
GO:0016494 		Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked.
ccr5_ccr5_chemokine_receptor CCR5
UniProtKB:P51681
Family Representative 		C-C chemokine receptor activity
GO:0016493 		Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked.
gnai2_gnai2_alpha_subunit GNAI2
UniProtKB:P04899
Family Representative 		G protein activity
GO:0003925 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
pik3cg_pi3k_gamma_catalytic_branch PIK3CG
UniProtKB:P48736
Family Representative 		1-phosphatidylinositol-3-kinase activity
GO:0016303 		Annotation Supported
A retained annotation or curated replacement supports this function, but core_functions does not yet reflect it.
rhoa_rhoa_cytoskeletal_switch RHOA
UniProtKB:P61586
Family Representative 		GTPase activity
GO:0003924 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
cxcl8_cxcl8_chemokine_ligand Interleukin-8 (CXCL8) chemokine ligand subfamily
PANTHER:PTHR12015:SF200
Family 		chemokine activity
GO:0008009 		Family Supported
Family review supports GO:0008009 FAMILY_WIDE. All members of PANTHER:PTHR12015 are secreted chemokines that act as chemotactic ligands for seven-transmembrane chemokine receptors.
cxcr2_cxcr2_chemokine_receptor C-X-C chemokine receptor type 2 subfamily
PANTHER:PTHR10489:SF689
Family 		C-X-C chemokine receptor activity
GO:0016494 		Family Function Unreviewed
Family review leaves GO:0016494 UNRESOLVED. C-X-C chemokine receptor activity is directly supported for CXCR3 by the cited ligand-response studies, but it is not exclusive to the CXCR3 subfamily: the broader family also contains CXCR1, CXCR2, CXCR4, CXCR5 and CXCR6 branches. CCR and atypical-receptor groups must be distinguished by ligand and signaling mechanism. The available CXCR3 representatives do not establish an exhaustive allowed-subfamily set, so family-wide applicability remains unresolved without denying the characterized CXCR3 activity.
ccr5_ccr5_chemokine_receptor C-C chemokine receptor type 5 subfamily
PANTHER:PTHR10489:SF686
Family 		C-C chemokine receptor activity
GO:0016493 		Family Function Unreviewed
The family review has no applicable adjudication supporting or excluding GO:0016493.
gnai2_gnai2_alpha_subunit Guanine nucleotide-binding protein G(i) subunit alpha-2 subfamily
PANTHER:PTHR10218:SF73
Family 		G protein activity
GO:0003925 		Family Review Missing
No supported structured family review is available for PANTHER:PTHR10218:SF73.
pik3cg_pi3k_gamma_catalytic_branch PI3K gamma catalytic branch family/ortholog group
PANTHER:PTHR10048
Family 		1-phosphatidylinositol-3-kinase activity
GO:0016303 		Family Scope Restricted
GO:0016303 is SUBFAMILY_ONLY; this family grounding does not establish the allowed subfamily scope. All three PI3K classes phosphorylate phosphatidylinositol at the 3-position: class III VPS34 (SF7, selected by the phosphoinositide_biosynthesis and phagosome_maturation modules, and its sole activity), the class II PI3Ks (SF28, SF29, SF30), and the class I catalytic subunits in vitro (SF107, SF33, SF34, SF35), whose PIK3CA and PIK3CD reviews keep the term. Not the type III PI4Ks. SF111 (C. elegans AGE-1, a class I catalytic subunit) is listed too; its review keeps the in vitro activity as non-core. For the class I subfamilies the scope records a measured in vitro activity, not the physiological one: in cells their main substrate is PI(4,5)P2. Read "safe" for those subfamilies with that caveat.
rhoa_rhoa_cytoskeletal_switch RhoA cytoskeletal switch family/ortholog group
PANTHER:PTHR24072
Family 		GTPase activity
GO:0003924 		Family Function Unreviewed
Family review leaves GO:0003924 UNRESOLVED. Full-length RHOJ is directly demonstrated to hydrolyze GTP, so RHOJ must not be labelled GTPase-deficient simply by analogy to atypical Rnd proteins. The benchmark product has a disrupted distal sequence and cannot inherit intact RHOJ kinetics. Across the broader family, nucleotide regulation and catalytic competence require branch- and product-specific evidence.

Gene-review completeness (4/6 grounded genes reviewed)

3 complete review(s) · 0 with deep research · 2 missing review · 4 reviewed but lacking deep research

Gene Review Complete Deep research
CXCL8 P10145 ✓ ✓ ✗
GNAI2 P04899 ✓ ✓ ✗
CXCR2 P25025 ✗ — —
CCR5 P51681 ✗ — —
PIK3CG P48736 ✓ 99/102 ✗
RHOA P61586 ✓ ✓ ✗

Details

Context
metazoaNCBITaxon:33208
extracellular regionGO:0005576 plasma membraneGO:0005886 cytosolGO:0005829 nucleusGO:0005634
Chemokine-mediated signaling pathwaySignaling Pathwaychemokine_signaling
chemokine-mediated signaling pathwayGO:0070098 interleukin-8-mediated signaling pathwayGO:0038112
Context
metazoaNCBITaxon:33208
extracellular regionGO:0005576 plasma membraneGO:0005886 cytosolGO:0005829 nucleusGO:0005634

Connections

Chemokine binding stabilizes the active conformation of CXCR1/CXCR2 or CCR5, promoting guanine nucleotide exchange on heterotrimeric Gi.
Released Gbetagamma and Galpha_i-GTP activate PI3Kgamma and Rho-family GTPase effectors to drive polarized leukocyte migration.
Part 1: chemokine-receptor engagement
Chemokine receptor engagementRegulatory Stepchemokine_receptor_engagement

Secreted chemokine ligands (exemplified by CXCL8/IL-8) engage seven-transmembrane chemokine receptors (CXCR1/CXCR2 for CXC chemokines; CCR5 for CC chemokines) via a two-site binding mechanism.

Annotons

CXCL8 chemokine ligand
cxcl8_cxcl8_chemokine_ligand
Participant: Family: Interleukin-8 (CXCL8) chemokine ligand subfamily
Family:
Interleukin-8 (CXCL8) chemokine ligand subfamilyPANTHER:PTHR12015:SF200
Representative Members: CXCL8UniProtKB:P10145

Function

chemokine activityGO:0008009

Processes

interleukin-8-mediated signaling pathwayGO:0038112 chemokine-mediated signaling pathwayGO:0070098 neutrophil chemotaxisGO:0030593

Locations

extracellular regionGO:0005576

Secreted ELR-positive CXC chemokine ligand that binds glycosaminoglycans and activates CXCR1/CXCR2 to initiate the interleukin-8-mediated signaling pathway and neutrophil chemotaxis.

PMID:8399143
Human and bovine granulocyte chemotactic protein-2: complete amino acid sequence and functional characterization as chemokines.
Demonstrates CXCL8 (IL-8) chemokine activity, neutrophil chemotaxis, and post-receptor signaling.
Both chemokines can also activate postreceptor mechanisms leading to release of gelatinase B by granulocytes.
PMID:32610344
Structural basis of CXC chemokine receptor 2 activation and signalling.
Resolves CXCL8 bound to CXCR2 in the active Gi-coupled signaling complex.
Here we present the cryo-electron microscopy structures of interleukin-8 (IL-8, also known as CXCL8)-activated human CXC chemokine receptor 2 (CXCR2) in complex with Gi protein, along with a crystal structure of CXCR2 bound to a designed allosteric antagonist.
CXCR2 chemokine receptor
cxcr2_cxcr2_chemokine_receptor
Participant: Family: C-X-C chemokine receptor type 2 subfamily
Family:
C-X-C chemokine receptor type 2 subfamilyPANTHER:PTHR10489:SF689
Representative Members: CXCR2UniProtKB:P25025

Function

C-X-C chemokine receptor activityGO:0016494

Processes

interleukin-8-mediated signaling pathwayGO:0038112 chemokine-mediated signaling pathwayGO:0070098 neutrophil chemotaxisGO:0030593

Locations

plasma membraneGO:0005886

High-affinity seven-transmembrane CXC chemokine receptor on neutrophils and endothelial cells that binds CXCL8 and other ELR-positive CXC chemokines to activate heterotrimeric Gi signaling.

PMID:32610344
Structural basis of CXC chemokine receptor 2 activation and signalling.
Demonstrates CXCL8-induced activation of human CXCR2 and coupling to Gi.
Here we present the cryo-electron microscopy structures of interleukin-8 (IL-8, also known as CXCL8)-activated human CXC chemokine receptor 2 (CXCR2) in complex with Gi protein, along with a crystal structure of CXCR2 bound to a designed allosteric antagonist.
CCR5 chemokine receptor
ccr5_ccr5_chemokine_receptor
Participant: Family: C-C chemokine receptor type 5 subfamily
Family:
C-C chemokine receptor type 5 subfamilyPANTHER:PTHR10489:SF686
Representative Members: CCR5UniProtKB:P51681

Function

C-C chemokine receptor activityGO:0016493

Processes

chemokine-mediated signaling pathwayGO:0070098 cell chemotaxisGO:0060326

Locations

plasma membraneGO:0005886

Seven-transmembrane CC-motif chemokine receptor that transduces CCL3, CCL4, and CCL5 signals via heterotrimeric Gi proteins to direct monocyte and T-cell chemotaxis.

PANTHER:PTN001628461
PAINT node PTN001628461 for chemokine receptors
Supports CCR5 participation in GO:0016493 (C-C chemokine receptor activity) and GO:0060326 (cell chemotaxis).
Part 2: heterotrimeric g protein coupling
Gi protein couplingRegulatory Stepgi_protein_coupling

Agonist-activated chemokine receptors act as guanine nucleotide exchange factors (GEFs) for pertussis toxin-sensitive Gi-family heterotrimeric G proteins, releasing Galpha_i-GTP and Gbetagamma dimers at the inner leaflet of the plasma membrane.

Annotons

GNAI2 alpha subunit
gnai2_gnai2_alpha_subunit
Participant: Family: Guanine nucleotide-binding protein G(i) subunit alpha-2 subfamily
Family:
Guanine nucleotide-binding protein G(i) subunit alpha-2 subfamilyPANTHER:PTHR10218:SF73
Representative Members: GNAI2UniProtKB:P04899

Function

G protein activityGO:0003925

Processes

chemokine-mediated signaling pathwayGO:0070098 interleukin-8-mediated signaling pathwayGO:0038112

Locations

plasma membraneGO:0005886

Inhibitory heterotrimeric G protein alpha subunit (Galpha_i2) coupled to CXCR1, CXCR2, and CCR5 that undergoes GDP-to-GTP exchange upon chemokine binding, releasing Gbetagamma to activate PI3Kgamma and PLCbeta2/3.

PMID:32610344
Structural basis of CXC chemokine receptor 2 activation and signalling.
Resolves direct coupling of CXCL8-bound CXCR2 to heterotrimeric Gi.
Here we present the cryo-electron microscopy structures of interleukin-8 (IL-8, also known as CXCL8)-activated human CXC chemokine receptor 2 (CXCR2) in complex with Gi protein, along with a crystal structure of CXCR2 bound to a designed allosteric antagonist.
PMID:37433790
Structural basis of CXC chemokine receptor 1 ligand binding and activation.
Resolves direct coupling of CXCL8-bound CXCR1 to Galpha_i.
Here, we solve the structure of CXCR1 complexed with CXCL8 and cognate G-proteins using cryo-EM, showing the detailed interactions between the receptor, the chemokine and Gαi protein.
Part 3: chemotaxis effector output
Chemotaxis effector outputRegulatory Stepchemotaxis_effector_output

PI3Kgamma and Rho-family GTPase branches downstream of Gi/Gbetagamma coordinate phosphoinositide polarization, actin remodeling, and directional leukocyte migration.

Annotons

PI3K gamma catalytic branch
pik3cg_pi3k_gamma_catalytic_branch
Participant: Family: PI3K gamma catalytic branch family/ortholog group
Family:
PI3K gamma catalytic branch family/ortholog groupPANTHER:PTHR10048
Representative Members: PIK3CGUniProtKB:P48736

Function

1-phosphatidylinositol-3-kinase activityGO:0016303

Processes

chemokine-mediated signaling pathwayGO:0070098 cell chemotaxisGO:0060326

Locations

plasma membraneGO:0005886 cytosolGO:0005829

Class IB phosphoinositide 3-kinase catalytic subunit (p110gamma) recruited by Gi-derived Gbetagamma dimers to generate PtdIns(3,4,5)P3 at the leading edge of chemotaxing leukocytes.

PANTHER:PTN000005674
PAINT node PTN000005674 for PIK3CG
Supports 1-phosphatidylinositol-3-kinase activity (GO:0016303) at the plasma membrane (GO:0005886).
RhoA cytoskeletal switch
rhoa_rhoa_cytoskeletal_switch
Participant: Family: RhoA cytoskeletal switch family/ortholog group
Family:
RhoA cytoskeletal switch family/ortholog groupPANTHER:PTHR24072
Representative Members: RHOAUniProtKB:P61586

Function

GTPase activityGO:0003924

Processes

chemokine-mediated signaling pathwayGO:0070098 cell chemotaxisGO:0060326

Locations

plasma membraneGO:0005886 cytosolGO:0005829

Small Rho-family GTPase switch that coordinates actomyosin contractility, uropod retraction, and integrin avidity maturation downstream of chemokine receptor activation.

PANTHER:PTN000632671
PAINT node PTN000632671 for RHOA
Supports GTPase activity (GO:0003924) and actin cytoskeleton organization (GO:0007015) at the plasma membrane (GO:0005886).