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Jung-Hoon Lee

Publications and source records attributed to Jung-Hoon Lee.

5 recordsLinked to original sources
PubMed2006

Intranasal delivery of the cytoplasmic domain of CTLA-4 using a novel protein transduction domain prevents allergic inflammation.

CTLA-4 is a negative regulator of T-cell activation, and its inhibitory effects can be accomplished either by competition with CD28 or by transmitting negative signals through its intracellular domain. To utilize the cytoplasmic domain of CTLA-4 to suppress allergic inflammation, we fused it to a novel protein-transduction domain in the human transcriptional factor Hph-1. Transduction efficiency was verified in vitro and in vivo after ocular, intranasal and intradermal administration. After transduction into T cells, the Hph-1-ctCTLA-4 fusion protein inhibited the production of interleukin (IL)-2, and downregulated CD69 and CD25. Intranasal administration of Hph-1-ctCTLA-4 resulted in markedly reduced infiltration of inflammatory cells, secretion of T helper type 2 (T(H)2) cytokines, serum IgE levels and airway hyper-responsiveness in a mouse model of allergic airway inflammation. These results indicated that Hph-1-ctCTLA-4 constitutes an effective immunosuppressive protein drug for potential use in the treatment of allergic asthma, via nasal administration.

Administration, Intranasal↗
PubMed2005

Structure of a peptide:N-glycanase-Rad23 complex: insight into the deglycosylation for denatured glycoproteins.

In eukaryotes, misfolded proteins must be distinguished from correctly folded proteins during folding and transport processes by quality control systems. Yeast peptide:N-glycanase (yPNGase) specifically deglycosylates the denatured form of N-linked glycoproteins in the cytoplasm and assists proteasome-mediated glycoprotein degradation by forming a complex with 26S proteasome through DNA repair protein, yRad23. Here, we describe the crystal structures of a yPNGase and XPC-binding domain of yRad23 (yRad23XBD, residues 238-309) complex and of a yPNGase-yRad23XBD complex bound to a caspase inhibitor, Z-VAD-fmk. yPNGase is formed with three domains, a core domain containing a Cys-His-Asp triad, a Zn-binding domain, and a Rad23-binding domain. Both N- and C-terminal helices of yPNGase interact with yRad23 through extensive hydrophobic interactions. The active site of yPNGase is located in a deep cleft that is formed with residues conserved in all PNGase members, and three sugar molecules are bound to this cleft. Complex structures in conjunction with mutational analyses revealed that the walls of the cleft block access to the active site of yPNGase by native glycoprotein, whereas the cleft is sufficiently wide to accommodate denatured glycoprotein, thus explaining the specificity of PNGase for denatured substrates.

Amino Acid Chloromethyl Ketones↗
PubMed2004

A case of bone marrow necrosis with thrombotic thrombocytopenic purpura as a manifestation of occult colon cancer.

Thrombotic thrombocytopenic purpura (TTP) is a disseminated form of thrombotic microangiopathy. Although most cases are held to be idiopathic, its association with malignancy is well recognized and it usually occurs at the terminal stage of cancer. Bone marrow necrosis (BMN) is another rare disorder defined pathologically as the necrosis of myeloid tissue and medullary stroma with preservation of bone. While hematologic malignancy is the most common underlying disease associated with BMN, it can also be caused by solid tumors. Neither TTP nor BMN associated with colon cancer has been reported. We describe here a patient with the rare association of TTP and BMN displayed as the first manifestation of an advanced colon cancer. The anemia and thrombocytopenia responded not to plasma exchange but to the combination chemotherapy. This case indicates that metastatic cancer should be included in the differential diagnosis of TTP and BMN, and that the chemotherapy may improve the detrimental clinical course.

Aged↗
PubMed2002

Cloning and expression of squalene synthase cDNA from hot pepper (Capsicum annuum L.).

We isolated and artificially expressed a cDNA clone of the Capsicum annuum squalene synthase (CASS) gene to elucidate the pattern of alternatively regulated two-branch point enzymes. The 1,674-bp CASS cDNA contained an open reading frame of 411 amino acids, yielding a predicted molecular mass of about 45 kDa. A deduced amino acid sequence comparison to other squalene syntheses showed identities with Nicotiana tabacum (91%), Nicotiana benthamiana (90%), Arabidopsis thaliana (79%), and rats (40%). The artificially expressed soluble form of the CASS enzyme was identified by the enzyme activity that converted FPP to squalene and by SDS-PAGE. A Southern blot analysis indicated that at least two copies of the squalene synthase gene exist in the hot pepper genome. In hot pepper, the regulation of the branch point enzymes, squalene synthase and sesquiterpene cyclase was investigated in the UV-challenged leaves of Capsicum annuum. The transcript level and enzyme activity of the CASS were slightly reduced by UV. However, those of the CASC were rapidly induced within 24 h and slowly decreased thereafter.

Base Sequence↗