CDB15:0001384 SFTPD — TLR4

Experimentally validated in Human; Orthology-inferred in Mouse, Rat, Frog, Zebrafish, Chicken, Macaque, Pig, Dog, Cow, Chimp, Horse, Marmoset, Sheep

Title

Journal:; Year Published:

Abstract

Human pulmonary surfactant protein D binds the extracellular domains of Toll-like receptors 2 and 4 through the carbohydrate recognition domain by a mechanism different from its binding to phosphatidylinositol and lipopolysaccharide.

Biochemistry, 2006; PubMed, Homo sapiens SFTPD — Homo sapiens TLR4

ABSTRACT: Pulmonary surfactant protein D (SP-D), a member of the collectin group of innate immune proteins, plays important roles in lipopolysaccharide (LPS) recognition. We have previously shown that surfactant protein A (SP-A), a homologous collectin, interacts with Toll-like receptor (TLR) 2, resulting in alteration of TLR2-mediated signaling. In this study, we found that natural and recombinant SP-Ds exhibited specific binding to the extracellular domains of soluble forms of recombinant TLR2 (sTLR2) and TLR4 (sTLR4). Binding was concentration- and Ca2+-dependent, and SP-D bound to N-glycosidase F-treated sTLRs on ligand blots. Anti-SP-D monoclonal antibody 7A10 blocked binding of SP-D to sTLR2 and sTLR4, but there was no inhibitory effect of monoclonal 7C6. Epitope mapping with recombinant proteins consisting of the carbohydrate recognition domain (CRD) and the neck domain plus CRD (NCRD) localized binding sites for 7A10 and 7C6 to sequential epitopes associated with the CRD and the neck domain, respectively. Interactions with 7A10 but not 7C6 were blocked by prior binding of the NCRD to sTLRs. Although antibody 7A10 significantly inhibited the binding of SP-D to its major surfactant-associated ligand, phosphatidylinositol (PI), and Escherichia coli Rc LPS, 7C6 enhanced binding to both molecules. An SP-D(E321Q, N323D) mutant with altered carbohydrate specificity exhibited attenuated PI binding but showed an increased level of binding to sTLRs. Thus, human SP-D binds the extracellular domains of TLR2 and TLR4 through its CRD by a mechanism different from its binding to PI and LPS.

Basic Information on SFTPD

Ligand Name: surfactant protein D

Other Symbols: SFTP4, SP-D, COLEC7

Ligand Location: secreted based on perplexity, uniprot

HGNC Gene Symbol Report: SFTPD

GeneCards: SFTPD

HGNC Gene Group: C-type lectin domain containing, Collectins

Functional Annotations for SFTPD

Gene Ontologies: PAN-GO, AmiGO 2

Expression Profile: Human Protein Atlas (RNA and protein), Human Cell Atlas (RNA), GEPIA cancer vs normal (RNA), GeneCards (RNA and protein)

Disease Annotations: MalaCards, OMIM, Open Targets Platform, DISEASES (text mining), AI summary (LLM)

Interactions with other Receptors for SFTPD

SFTPD — LY96 ・ SFTPD — LAIR1 ・ SFTPD — SIRPA ・ SFTPD — LRP1 ・ SFTPD — OSCAR ・ SFTPD — SIRPB1 ・ SFTPD — TLR2

Basic Information on TLR4

Receptor Name: toll like receptor 4

Other Symbols: hToll, CD284, TLR-4, ARMD10

Receptor Location: cell membrane based on hpa, perplexity, uniprot

HGNC Gene Symbol Report: TLR4

GeneCards: TLR4

HGNC Gene Group: TIR domain containing, CD molecules

Functional Annotations for TLR4

Gene Ontologies: PAN-GO, AmiGO 2

Expression Profile: Human Protein Atlas (RNA and protein), Human Cell Atlas (RNA), GEPIA cancer vs normal (RNA), GeneCards (RNA and protein)

Disease Annotations: MalaCards, OMIM, Open Targets Platform, DISEASES (text mining), AI summary (LLM)

Interactions with other Ligands for TLR4

BGN — TLR4 ・ DEFB4A — TLR4 ・ HSP90B1 — TLR4 ・ HSPA1A — TLR4 ・ S100A8 — TLR4 ・ S100A9 — TLR4 ・ ZG16B — TLR4 ・ DCN — TLR4 ・ FGA — TLR4 ・ FGB — TLR4 ・ FGG — TLR4 ・ PRG4 — TLR4 ・ AHSG — TLR4 ・ ANXA2 — TLR4 ・ CCN1 — TLR4 ・ CIRBP — TLR4 ・ CXCL10 — TLR4 ・ FCN2 — TLR4 ・ HMGB1 — TLR4 ・ HP — TLR4 ・ HSPA4 — TLR4 ・ LGALS9 — TLR4 ・ MMP9 — TLR4 ・ NAMPT — TLR4 ・ RBP4 — TLR4 ・ RETN — TLR4 ・ S100A1 — TLR4 ・ S100A12 — TLR4 ・ S100A4 — TLR4 ・ SAA1 — TLR4 ・ SFTPA1 — TLR4 ・ TNC — TLR4 ・ WNT5A — TLR4