Article

CLIMP-63 is a gentamicin-binding protein that is involved in drug-induced cytotoxicity.

Oregon Hearing Research Center, Oregon Health & Science University, Portland, 97239, USA.
Cell Death & Disease (Impact Factor: 5.18). 11/2010; 1:e102. DOI: 10.1038/cddis.2010.80
Source: PubMed

ABSTRACT Aminoglycoside-induced nephrotoxicity and ototoxicity is a major clinical problem. To understand how aminoglycosides, including gentamicin, induce cytotoxicity in the kidney proximal tubule and the inner ear, we identified gentamicin-binding proteins (GBPs) from mouse kidney cells by pulling down GBPs with gentamicin-agarose conjugates and mass spectrometric analysis. Among several GBPs specific to kidney proximal tubule cells, cytoskeleton-linking membrane protein of 63 kDa (CLIMP-63) was the only protein localized in the endoplasmic reticulum, and was co-localized with gentamicin-Texas Red (GTTR) conjugate after cells were treated with GTTR for 1 h. In western blots, kidney proximal tubule cells and cochlear cells, but not kidney distal tubule cells, exhibited a dithiothreitol (DTT)-resistant dimer band of CLIMP-63. Gentamicin treatment increased the presence of DTT-resistant CLIMP-63 dimers in both kidney proximal (KPT11) and distal (KDT3) tubule cells. Transfection of wild-type and mutant CLIMP-63 into 293T cells showed that the gentamicin-dependent dimerization requires CLIMP-63 palmitoylation. CLIMP-63 siRNA transfection enhanced cellular resistance to gentamicin-induced toxicity, which involves apoptosis, in KPT11 cells. Thus, the dimerization of CLIMP-63 is likely an early step in aminoglycoside-induced cytotoxicity in the kidney and cochlea. Gentamicin also enhanced the binding between CLIMP-63 and 14-3-3 proteins, and we also identified that 14-3-3 proteins are involved in gentamicin-induced cytotoxicity, likely by binding to CLIMP-63.

0 Bookmarks
 · 
213 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: CKAP4, one kind of type II trans-membrane protein, plays an important role to maintain endoplasmic reticulum structure and inhibits the proliferation of bladder cancer cells by combining its ligand anti-proliferative factor (APF). However, the biological function of CKAP4 in the progression of liver cancer has not been clearly demonstrated. In the present study, we knocked down or overexpressed CKAP4 in hepatocellular carcinoma (HCC) cells and cell proliferation, invasion, and migration capacities were investigated by CCK-8 and transwell assays. In vivo tumor model in mice was used to evaluate the role of CKAP4 on growth and metastasis of HCC. The data documented that HCC cells with high CKAP4 levels were featured by low proliferation capability as well as low invasion potential. Interestingly, we found that CKAP4 suppressed the activation of epithelial growth factor receptor (EGFR) signaling, which may partly explain the role of CKAP4 in cell biological behavior of HCC. Further study revealed that CKAP4 could associate with EGFR at basal status and the complex was reduced upon EGF stimulation, leading to release EGFR into cytoplasm. Thus, we demonstrate the novel mechanism, for the first time, expression of CKAP4 regulates progression and metastasis of HCC and it may provide therapeutic values in this tumor.
    Tumor Biology 05/2014; 35(8). DOI:10.1007/s13277-014-2000-3 · 2.84 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Aminoglycosides exhibit relatively poor activity against intracellular Salmonella due to their low permeability across eukaryotic cell membranes. Previously, we identified the unique ability of AR-12, a celecoxib-derived small-molecule agent, to eradicate intracellular Salmonella Typhimurium in macrophages by facilitating autophagosome formation and suppressing Akt kinase signaling. In light of this unique mode of antibacterial action, we investigated the ability of AR-12 to sensitize intracellular Salmonella to aminoglycosides in macrophages and in an animal model. The antibacterial activities of AR-12 combined with various aminoglycosides, including streptomycin, kanamycin, gentamicin and amikacin, against intracellular S. Typhimurium in murine RAW264.7 macrophages were assessed. Cells were infected with S. Typhimurium followed by treatment with AR-12, individual aminoglycoside, or in combination for 24 hours. The in vivo efficacies of AR-12, alone or in combination with gentamicin or amikacin, were also assessed by treating S. Typhimurium-infected Balb/c mice daily for 14 consecutive days. Exposure of S. Typhimurium-infected RAW264.7 cells to a combination of AR-12 with individual aminoglycosides led to a greater reduction in bacterial survival (P < 0.05), both intracellular and extracellular, relative to aminoglycosides alone. This sensitizing effect, however, was not associated with increased aminoglycoside penetration into bacteria or macrophages. Moreover, daily intraperitoneal injection of AR-12 at 0.1 mg/kg significantly increased the in vivo efficacy of gentamicin and amikacin in prolonging the survival of S. Typhimurium-infected mice. These findings indicate that the unique ability of AR-12 to enhance the in vivo efficacy of aminoglycosides might have translational potential to develop novel strategies for the treatment of salmonellosis.
    Antimicrobial Agents and Chemotherapy 09/2014; 58(12). DOI:10.1128/AAC.03778-14 · 4.45 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The functions of cytoskeleton-associated membrane protein 4 (CKAP4), one kind of type II transmembrane protein, are associated with the palmitoyl acyltransferase DHHC2. The objective of the current study was to investigate CKAP4/DHHC2 expression and its prognostic significance in patients with hepatocellular carcinoma (HCC).
    Cancer 02/2014; 120(10):1520-31. DOI:10.1002/cncr.28593 · 5.20 Impact Factor

Full-text (2 Sources)

Download
69 Downloads
Available from
May 26, 2014