RESUMO
Inositol 1,4,5-triphosphate-mediated calcium (IP3-Ca2+) signal cascade is an essential process in sweet, bitter, and umami taste signal transduction. Although the main components of this cascade have been identified, the candidate regulators of them in taste tissues are still unclear. In an effort to identify genes involved in taste signal transduction, we found that a gene encoding lymphoid-restricted membrane protein (Lrmp/Jaw1) was expressed in mouse taste tissues. Here we report that Lrmp/Jaw1 is specifically expressed in sweet, bitter, and umami taste receptor-expressing cells of mouse circumvallate, foliate, and fungiform papillae. In addition to this specific expression patterns, we found that Lrmp/Jaw1 is associated with type III IP3 receptor (IP3R3) via its coiled-coil domain in the COS7 heterologous expression system. These results raise the possibility that Lrmp/Jaw1 interacts with IP3R3 in taste cells and suggest an important role for Lrmp/Jaw1 in the IP3-Ca2+ signal cascade in sweet, bitter, and umami taste signal transduction.
Assuntos
Proteínas de Membrana/metabolismo , Papilas Gustativas/metabolismo , Paladar/fisiologia , Animais , Células COS , Sinalização do Cálcio , Chlorocebus aethiops , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Masculino , Proteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Transdução de Sinais , Paladar/genética , Papilas Gustativas/citologia , Papilas Gustativas/ultraestruturaRESUMO
Group 2 major mite allergens Der f 2 and Der p 2 are classified into the recently identified group of MD-2-related lipid-recognition (ML) proteins, but the ligands and biological functions of these allergens are unknown. We have obtained a high-quality NMR structure for Der f 2, and found that it is more similar to the crystal structure of NPC2, a distant homologue, than to that of Der p 2, in terms of the separation and angle between the two major beta-sheets. This made us propose that ML proteins undergo clamshell-like motions that change the sizes of ligand-binding spaces inside their immunoglobulin-fold beta-sandwich to accommodate lipid molecules. This type of motion in lipopolysaccaride recognition of MD-2 is suggested to be likely as well by structural models. We also report the applicability of NMR differential exchange broadening experiments for complexes of intact monoclonal antibodies and antigens; using this technique, we have detected the conformational epitopes for monoclonal antibodies 15E11 and 13A4 as two separate surface patches.
Assuntos
Antígenos de Dermatophagoides/química , Antígenos de Dermatophagoides/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais/imunologia , Reações Antígeno-Anticorpo , Antígenos de Dermatophagoides/fisiologia , Antígenos de Superfície/química , Proteínas de Artrópodes , Proteínas de Transporte/química , Espectroscopia de Ressonância de Spin Eletrônica , Epitopos/imunologia , Lipopolissacarídeos/metabolismo , Antígeno 96 de Linfócito , Camundongos , Modelos Moleculares , Dados de Sequência Molecular , Ressonância Magnética Nuclear Biomolecular , Estrutura Terciária de Proteína , Alinhamento de Sequência , Proteínas de Transporte Vesicular/químicaRESUMO
A recombinant Rhizobium strain, PBK3-IS, that constitutively expressed the oxygenase component of carbazole 1,9a-dioxygenase from Sphingomonas sp. strain KA1, was constructed. In the water-cultured siratro rhizospheres inoculated with strain PBK3-IS, 48% of the dibenzofuran was removed within 3 days (initial substrate, 25 microg). Similar results were obtained in soil-cultured siratro rhizospheres using sterile vermiculite. When non-sterile field soils were used instead of sterile vermiculite, the inoculated recombinant strain could grow on the siratro root in all soils tested, except for wet paddy field.