Yumi Kim

Coronavirus disease 2019 (COVID-19), the current pandemic disease, is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Type I and III interferons (IFNs) are innate cytokines that are important in the first-line defense against viruses. Similar to many other viruses, SARS-CoV-2 has evolved mechanisms for evading the antiviral effects of type I and III IFNs at multiple levels, including the induction of IFN expression and cellular responses to IFNs. In this review,

The non-visual arrestins, arrestin-2 and arrestin-3, play a critical role in regulating the signaling and trafficking of many G protein-coupled receptors (GPCRs). Molecular insight into the role of arrestins in GPCR trafficking has suggested that arrestin interaction with clathrin, beta(2)-adaptin (the beta-subunit of the adaptor protein AP2), and phosphoinositides contributes to this process. In the present study, we have attempted to better define the molecular basis and functional role of arr

We explored the role of antigen valency in B cell receptor (BCR) activation and rearrangement of intracellular MHC class II compartments as factors that contribute to the efficacy of antigen presentation. Using primary B cells that express a hen egg lysozyme (HEL)-specific BCR, we found that oligomeric HEL more efficiently promoted both BCR activation and internalization than did monovalent HEL, although monovalent HEL, unlike monovalent Fab fragments of anti-Ig, readily triggered the BCR. Nonet

Asthma is a chronic obstructive airway disease that involves inflammation of the respiratory tract. Biological contaminants in indoor air can induce innate and adaptive immune responses and inflammation, resulting in asthma pathology. Epidemiologic surveys indicate that the prevalence of asthma is higher in developed countries than in developing countries. The prevalence of asthma in Korea has increased during the last several decades. This increase may be related to changes in housing styles, w

Arrestins play an important role in regulating the function of G protein-coupled receptors including receptor desensitization, internalization, down-regulation, and signaling via nonreceptor tyrosine kinases and mitogen-activated protein kinases. Previous studies have revealed that arrestins themselves are also subject to regulation. In the present study, we focused on identifying potential mechanisms involved in regulating the function of arrestin-3. Using metabolic labeling, phosphoamino acid

Lymphocyte-specific protein-tyrosine kinase (Lck) plays an essential role in T cell receptor (TCR) signaling and T cell development, but its activation mechanism is not fully understood. To explore the possibility that plasma membrane (PM) lipids control TCR signaling activities of Lck, we measured the membrane binding properties of its regulatory Src homology 2 (SH2) and Src homology 3 domains. The Lck SH2 domain binds anionic PM lipids with high affinity but with low specificity. Electrostatic

TLR9 signaling is involved in regulating adipose tissue inflammation and controlling obesity and the metabolic syndrome.

High neonatal susceptibility to meningitis has been attributed to the anatomical barriers that act to protect the central nervous system (CNS) from infection being immature and not fully developed. However, the mechanisms by which pathogens breach CNS barriers are poorly understood. Using the Armstrong strain of lymphocytic choriomeningitis virus (LCMV) to study virus propagation into the CNS during systemic infection, we demonstrate that mortality in neonatal, but not adult, mice is high after

TLRs are divided into two groups based on their subcellular localization patterns. TLR1, 2, 4, 5, and 6 are expressed on the cell surface, whereas the nucleotide-sensing TLRs, such as TLR3, 7, 8, and 9 stay mainly inside cells. The polytopic membrane protein UNC93B1 physically interacts with the nucleotide-sensing TLRs and delivers them from the endoplasmic reticulum to endolysosomes, where the TLRs recognize their ligands and initiate signaling. In cells with nonfunctional UNC93B1, the nucleic

Brazilin (7,11b-dihydrobenz[b]indeno-[1,2-d]pyran-3,6a,9,10(6H)- tetrol) was found to have hypoglycemic action and increase glucose metabolism in experimental diabetic animals. In order to investigate the mechanism of hypoglycemic action of brazilin, the effects of brazilin on glucose transport, insulin receptor autophosphorylation, and protein kinase C(PKC) activity in 3T3-L1 cells were studied. Brazilin increased basal glucose transport in 3T3-L1 fibroblasts and adipocytes. However, insulin-st

Paneth cells are one of the principal epithelial cell types in the small intestine, located at the base of intestinal crypts. Paneth cells play key roles in intestinal host-microbe homeostasis via granule secretion, and their dysfunction is implicated in pathogenesis of several diseases including Crohn's disease. Despite their physiological importance, study of Paneth cells has been hampered by the limited accessibility and lack of labeling methods. In this study, we developed a simple in vivo i