Identification and characterization of endogenous Langerin ligands in murine extracellular matrix.
Langerin is a C-type lectin that is expressed by Langerhans cells (LC) and related immune cells, and believed to play an important role in antigen recognition and uptake. To determine if Langerin has endogenous ligands, we generated S protein binding, bacterial recombinant, mouse soluble Langerin, and utilized it as a probe. Recombinant soluble Langerin did not bind to lymph node or spleen cells, or keratinocytes as assessed via flow cytometry. However, Langerin did bind to surfaces of primary skin fibroblasts and NIH3T3 cells. "Ligand blotting" of fibroblast membrane-enriched fractions with Langerin revealed reproducible binding to 140 and 240 kDa proteins resolved in reduced denaturing gels. Characterization of these proteins using mass spectrometry suggested types I and III procollagen and fibronectin as candidate ligands. Langerin bound to type I procollagen that was immunoprecipitated from fibroblast lysates, but did not bind to fibronectin that was immunoprecipitated from fibroblast-conditioned media or mouse plasma fibronectin. These results indicate that Langerin selectively interacts with at least one ligand in extracellular matrix (type I procollagen). Langerin may have an unanticipated role in cell-matrix interactions that modulate LC development, localization, or function.
Dermatology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Massachusetts, USA.
Yayoi
Y
Tada
Elisabeth
E
Riedl
Mark S
MS
Lowenthal
Lance A
LA
Liotta
David M
DM
Briner
Erika C
EC
Crouch
Mark C
MC
Udey
D000595:Amino Acid Sequence; D000818:Animals; D000954:Antigens, Surface / Q000378:metabolism*; D019556:COS Cells; D002522:Chlorocebus aethiops; D024042:Collagen Type I / Q000378:metabolism*; D024061:Collagen Type III / Q000032:analysis / Q000502:physiology; D005109:Extracellular Matrix / Q000378:metabolism*; D005347:Fibroblasts / Q000737:chemistry / Q000166:cytology / Q000502:physiology; D005353:Fibronectins / Q000032:analysis / Q000502:physiology; D005434:Flow Cytometry; D006801:Humans; D047468:Immunoprecipitation; D015603:Keratinocytes / Q000737:chemistry / Q000166:cytology / Q000502:physiology; D037181:Lectins, C-Type / Q000378:metabolism*; D008024:Ligands; D037241:Mannose-Binding Lectins / Q000378:metabolism*; D013058:Mass Spectrometry; D008546:Melanoma, Experimental; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D041681:NIH 3T3 Cells; D011485:Protein Binding; D011994:Recombinant Proteins / Q000032:analysis; D012867:Skin / Q000737:chemistry / Q000166:cytology
D000954:Antigens, Surface; C498497:Cd207 protein, mouse; D024042:Collagen Type I; D024061:Collagen Type III; D005353:Fibronectins; D037181:Lectins, C-Type; D008024:Ligands; D037241:Mannose-Binding Lectins; D011994:Recombinant Proteins