• BMB Reports
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• v.55 no.10
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• pp.488-493
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• 2022

The specific pair of heat shock protein 70 (Hsp70) and Hsp40 constitutes an essential molecular chaperone system involved in numerous cellular processes, including the proper folding/refolding and transport of proteins. Hsp40 family members are characterized by the presence of a conserved J-domain (JD) that functions as a co-chaperone of Hsp70. Tumorous imaginal disc 1 (Tid1) is a tumor suppressor protein belonging to the DNAJA3 subfamily of Hsp40 and functions as a co-chaperone of the mitochondrial Hsp70, mortalin. In this work, we performed nuclear magnetic resonance spectroscopy to determine the solution structure of JD and its interaction with the glycine/phenylalanine-rich region (GF-motif) of human Tid1. Notably, Tid1-JD, whose conformation was consistent with that of the DNAJB1 JD, appeared to stably interact with its subsequent GF-motif region. Collectively with our sequence analysis, the present results demonstrate that the functional and regulatory mode of Tid1 resembles that of the DNAJB1 subfamily members rather than DNAJA1 or DNAJA2 subfamily proteins. Therefore, it is suggested that an allosteric interaction between mortalin and Tid1 is involved in the mitochondrial Hsp70/Hsp40 chaperone system.

• Proceedings of the Korean Aquaculture Society Conference
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• 2006.05a
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• pp.476-478
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• 2006

To analyze subcellular localization of betanodavirus protein B2, a plasmid expressing Betanodavirus protein B2 fused to enhanced green fluorescent protein (EGFP-Nl) was constructed. The transient expression of full-length B2 fused to EGFP in GF cells confirmed the equal distribution of protein B2 between cytoplasm and nucleus. However, transfection of N-terminal half of the B2 revealed that this truncated form predominantly localized to the cytoplasm. By using several deletion mutants and point mutants, we determined the regions and/or motif responsible for the subcellular localization of betanodavirus.

• The Korean Journal of Physiology and Pharmacology
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• v.15 no.1
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• pp.31-36
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• 2011

To understand the roles of purinergic receptors and cellular molecules below the receptors in the vascular inflammatory response, we determined if extracellular nucleotides up-regulated chemokine expression in vascular smooth muscle cells (VSMCs). Human aortic smooth muscle cells (AoSMCs) abundantly express $PSY_1$, $PSY_6$, and $PSY_{11}$ receptors, which all respond to extracellular nucleotides. Exposure of human AoSMCs to $NAD^+$, an agonist of the human $PSY_{11}$ receptor, and $NADP^+$ as well as ATP, an agonist for $PSY_1$ and $PSY_{11}$ receptors, caused increase in chemokine (C-C motif) ligand 2 gene (CCL2) transcript and CCL2 release; however, UPT did not affect CCL2 expression. CCL2 release by $NAD^+$ and $NADP^+$ was inhibited by a concentration dependent manner by suramin, an antagonist of P2-purinergic receptors. $NAD^+$ and $NADP^+$ activated protein kinase C and enhanced phosphorylation of mitogen-activated protein kinases and Akt. $NAD^+$- and $NADP^+$-mediated CCL2 release was significantly attenuated by SP6001250, U0126, LY294002, Akt inhibitor IV, RO318220, GF109203X, and diphenyleneiodium chloride. These results indicate that extracellular nucleotides can promote the proinflammatory VSMC phenotype by up-regulating CCL2 expression, and that multiple cellular elements, including phosphatidylinositol 3-kinase, Akt, protein kinase C, and mitogen-activated protein kinases, are involved in that process.

• The Korean Journal of Physiology and Pharmacology
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• v.19 no.6
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• pp.549-555
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• 2015

We attempted to investigate molecular mechanisms underlying phenotypic change of vascular smooth muscle cells (VSMCs) by determining signaling molecules involved in chemokine production. Treatment of human aortic smooth muscle cells (HAoSMCs) with thrombin resulted not only in elevated transcription of the (C-C motif) ligand 11 (CCL11) gene but also in enhanced secretion of CCL11 protein. Co-treatment of HAoSMCs with GF109230X, an inhibitor of protein kinase C, or GW5074, an inhibitor of Raf-1 kinase, caused inhibition of ERK1/2 phosphorylation and significantly attenuated expression of CCL11 at transcriptional and protein levels induced by thrombin. Both Akt phosphorylation and CCL11 expression induced by thrombin were attenuated in the presence of pertussis toxin (PTX), an inhibitor of Gi protein-coupled receptor, or LY294002, a PI3K inhibitor. In addition, thrombin-induced production of CCL11 was significantly attenuated by pharmacological inhibition of Akt or MEK which phosphorylates ERK1/2. These results indicate that thrombin is likely to promote expression of CCL11 via PKC/Raf-1/ERK1/2 and PTX-sensitive protease-activated receptors /PI3K/Akt pathways in HAoSMCs. We propose that multiple signaling pathways are involved in change of VSMCs to a secretory phenotype.