Dataset Information

Peroxiredoxin 6 mediates Gαi protein-coupled receptor inactivation by cJun kinase.

ABSTRACT: Inactivation of opioid receptors limits the therapeutic efficacy of morphine-like analgesics and mediates the long duration of kappa opioid antidepressants by an uncharacterized, arrestin-independent mechanism. Here we use an iterative, discovery-based proteomic approach to show that following opioid administration, peroxiredoxin 6 (PRDX6) is recruited to the opioid receptor complex by c-Jun N-terminal kinase (JNK) phosphorylation. PRDX6 activation generates reactive oxygen species via NADPH oxidase, reducing the palmitoylation of receptor-associated Gαi in a JNK-dependent manner. Selective inhibition of PRDX6 blocks Gαi depalmitoylation, prevents the enhanced receptor G-protein association and blocks acute analgesic tolerance to morphine and kappa opioid receptor inactivation in vivo. Opioid stimulation of JNK also inactivates dopamine D2 receptors in a PRDX6-dependent manner. We show that the loss of this lipid modification distorts the receptor G-protein association, thereby preventing agonist-induced guanine nucleotide exchange. These findings establish JNK-dependent PRDX6 recruitment and oxidation-induced Gαi depalmitoylation as an additional mechanism of Gαi-G-protein-coupled receptor inactivation.Opioid receptors are important modulators of nociceptive pain. Here the authors show that opioid receptor activation recruits peroxiredoxin 6 (PRDX6) to the receptor-Gαi complex by c-Jun N-terminal kinase, resulting in Gαi depalmitoylation and enhanced receptor-Gαi association.

SUBMITTER: Schattauer SS

PROVIDER: S-EPMC5622097 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:BACKGROUND: Tazarotene-induced gene 1 (TIG1) is a retinoid-inducible type II tumour suppressor gene. The B isoform of TIG1 (TIG1B) inhibits growth and invasion of cancer cells. Expression of TIG1B is frequently downregulated in various cancer tissues; however, the expression and activities of the TIG1A isoform are yet to be reported. Therefore, this study investigated the effects of the TIG1A and TIG1B isoforms on cell growth and gene expression profiles using colon cancer cells. METHODS: TIG1A and TIG1B stable clones derived from HCT116 and SW620 colon cancer cells were established using the GeneSwitch system; TIG1 isoform expression was induced by mifepristone treatment. Cell growth was assessed using the WST-1 cell proliferation and colony formation assays. RNA interference was used to examine the TIG1 mediating changes in cell growth. Gene expression profiles were determined using microarray and validated using real-time polymerase chain reaction, and Western blot analyses. RESULTS: Both TIG1 isoforms were expressed at high levels in normal prostate and colon tissues and were downregulated in colon cancer cell lines. Both TIG1 isoforms significantly inhibited the growth of transiently transfected HCT116 cells and stably expressing TIG1A and TIG1B HCT116 and SW620 cells. Expression of 129 and 55 genes was altered upon induction of TIG1A and TIG1B expression, respectively, in stably expressing HCT116 cells. Of the genes analysed, 23 and 6 genes were upregulated and downregulated, respectively, in both TIG1A and TIG1B expressing cells. Upregulation of the G-protein-coupled receptor kinase 5 (GRK5) was confirmed using real-time polymerase chain reaction and Western blot analyses in both TIG1 stable cell lines. Silencing of TIG1A or GRK5 expression significantly decreased TIG1A-mediated cell growth suppression. CONCLUSIONS: Expression of both TIG1 isoforms was observed in normal prostate and colon tissues and was downregulated in colon cancer cell lines. Both TIG1 isoforms suppressed cell growth and stimulated GRK5 expression in HCT116 and SW620 cells. Knockdown of GRK5 expression alleviated TIG1A-induced growth suppression of HCT116 cells, suggesting that GRK5 mediates cell growth suppression by TIG1A. Thus, TIG1 may participate in the downregulation of G-protein coupled signaling by upregulating GRK5 expression.

Dataset Information

Peroxiredoxin 6 mediates Gαi protein-coupled receptor inactivation by cJun kinase.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets