scholarly journals Expression of the genes for the ferritin H and L subunits in rat liver and heart. Evidence for tissue-specific regulations at pre- and post-translational levels

1991 ◽  
Vol 275 (3) ◽  
pp. 813-816 ◽  
Author(s):  
G Cairo ◽  
E Rappocciolo ◽  
L Tacchini ◽  
L Schiaffonati

The proportion of ferritin light-chain and heavy-chain subunits (L and H) present in the ferritin multimeric shell varies between different tissues. To identify the regulatory mechanisms responsible for the greater amount of L in liver than in heart isoferritins, we analysed ferritin-gene expression at the RNA and protein levels in these two tissues of the rat. In the heart the ratio between the amount of L and H, at the level both of synthesis and accumulation, is about 1 and is the same as the ratio between their respective mRNAs. In contrast, in the liver, the ratio between the L- and H-mRNAs is approx. 2 and cannot entirely explain the large predominance of L in isoferritins in this tissue. Since in the liver the L-mRNA is neither preferentially associated with polyribosomes nor translated more efficiently than its H- counterpart, it seems that the liver-specific isoferritin profile is determined by a combination of pre- and post-translational mechanisms, whereas in heart the post-translational regulation does not seem to be relevant and the tissue-specific pattern is determined at the level of mRNA accumulation.

Diabetes ◽  
1989 ◽  
Vol 38 (6) ◽  
pp. 752-757 ◽  
Author(s):  
D. N. Papachristou ◽  
K. Pham ◽  
H. H. Zingg ◽  
Y. C. Patel

2019 ◽  
Vol 166 (4) ◽  
pp. 309-315 ◽  
Author(s):  
Taro Watanabe ◽  
Noriyuki Kioka ◽  
Kazumitsu Ueda ◽  
Michinori Matsuo

Abstract ATP-binding cassette protein G1 (ABCG1) plays an important role in eliminating excess cholesterol from macrophages and in the formation of high-density lipoprotein (HDL), which contributes to the prevention and regression of atherosclerosis. The post-translational regulation of ABCG1 remains elusive, although phosphorylation by protein kinase A destabilizes ABCG1 proteins. We examined the phosphorylation of ABCG1 using HEK293 and Raw264.7 cells. ABCG1 phosphorylation was enhanced by treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA), a protein kinase C (PKC) activator. PKC activation by TPA increased ABCG1 protein levels and promoted ABCG1-dependent cholesterol efflux to HDL. This activity was suppressed by Go6976, a PKCα/βI inhibitor, suggesting that PKC activation stabilizes ABCG1. To confirm this, the degradation rate of ABCG1 was analysed; ABCG1 degradation was suppressed upon PKC activation, suggesting that PKC phosphorylation regulates ABCG1 levels. To confirm this involvement, we co-expressed ABCG1 and a constitutively active form of PKCα in HEK cells. ABCG1 was increased upon co-expression. These results suggest that PKC-mediated phosphorylation, probably PKCα, stabilizes ABCG1, consequently increasing ABCG1-mediated cholesterol efflux, by suppressing ABCG1 degradation. PKC activation could thus be a therapeutic target to suppress the development of atherosclerosis.


2021 ◽  
Author(s):  
Bin Qiu ◽  
Zhaohui Zhong ◽  
Shawn Righter ◽  
Yuxue Xu ◽  
Jun Wang ◽  
...  

Abstract FK506-binding protein 51 (encoded by Fkpb51) has been associated with stress-related mental illness. To identify its function, we studied the morphological consequences of Fkbp51 deletion. Artificial Intelligence-assist morphological analysis identified that Fkbp51 knock-out (KO) mice possess more elongated CA and DG but shorter in height in coronal section when compared to WT. Primary cultured Fkbp51 KO hippocampal neurons were shown to exhibit larger dendritic outgrowth than wild-type (WT) controls, pharmacological manipulation experiments suggest that this may occur through regulation of microtubule-associated protein. Both in vitro primary culture and in vivo labeling support that FKBP51 regulates microtubule-associated protein expression. Furthermore, in the absence of differences in mRNA expression, Fkbp51 KO hippocampus exhibited decreases in βIII-tubulin, MAP2, and Tau protein levels, but a greater than 2.5-fold increase in Parkin protein. Overexpression and knock-down FKBP51 demonstrated that FKBP51 negatively regulates Parkin in a dose-dependent and ubiquitin-mediated manner. These results indicate a potential novel post-translational regulatory of Parkin by FKBP51 and significance of their interaction on disease onset.


2016 ◽  
Vol 147 (2) ◽  
pp. 105-125 ◽  
Author(s):  
Elke Bocksteins

Members of the electrically silent voltage-gated K+ (Kv) subfamilies (Kv5, Kv6, Kv8, and Kv9, collectively identified as electrically silent voltage-gated K+ channel [KvS] subunits) do not form functional homotetrameric channels but assemble with Kv2 subunits into heterotetrameric Kv2/KvS channels with unique biophysical properties. Unlike the ubiquitously expressed Kv2 subunits, KvS subunits show a more restricted expression. This raises the possibility that Kv2/KvS heterotetramers have tissue-specific functions, making them potential targets for the development of novel therapeutic strategies. Here, I provide an overview of the expression of KvS subunits in different tissues and discuss their proposed role in various physiological and pathophysiological processes. This overview demonstrates the importance of KvS subunits and Kv2/KvS heterotetramers in vivo and the importance of considering KvS subunits and Kv2/KvS heterotetramers in the development of novel treatments.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zin Zin Ei ◽  
Kanuengnit Choochuay ◽  
Alisa Tubsuwan ◽  
Decha Pinkaew ◽  
Maneewan Suksomtip ◽  
...  

AbstractCisplatin (CDDP) induces senescence characterized by senescence-associated secretory phenotypes (SASP) and the unfolded protein response (UPR). In this study, we investigated the proteins related to the UPR during the senescence cell fate. Strikingly, we found that one of the critical ER-resident proteins, GRP78/BiP, was significantly altered. Here we show that GRP78 levels differentially expressed depending on non-small lung cancer subtypes. GRP78 indeed regulates the evasion of senescence in adenocarcinoma A549 cells, in which the increased GRP78 levels enable them to re-proliferate after CDDP removal. Conversely, GRP78 is downregulated in the senescence H460 cells, making them lacking senescence evasion capability. We observed that the translational regulation critically contributed to the GRP78 protein levels in CDDP-induces senescence. Furthermore, the increased GRP78 level during senescence confers resistance to senolytic drug, Bortezomib, as observed by a twofold increase in IC50 in A549 senescence cells compared to the wild-type. This observation is also consistent in the cells that have undergone genetic manipulation by transfection with pcDNA3.1(+)-GRP78/BiP plasmids and pSpCas9(BB)-2A-Puro containing guide RNA sequence targeting GRP78 exon 3 to induce the overexpression and downregulation of GRP78 in H460 cells, respectively. Our findings reveal a unique role of GRP78 on the senescence evasion cell fate and senolytic drug resistance after cisplatin-based chemotherapy.


2021 ◽  
Vol 12 ◽  
Author(s):  
Yung Jae Kim ◽  
Byoung Jun Choi ◽  
Si Hyoung Park ◽  
Han Byeol Lee ◽  
Ji Eun Son ◽  
...  

Peptidoglycan (PG) hydrolases play important roles in various aspects of bacterial physiology, including cytokinesis, PG synthesis, quality control of PG, PG recycling, and antibiotic resistance. However, the regulatory mechanisms of their expression are poorly understood. In this study, we have uncovered novel regulatory mechanisms of the protein levels of the synthetically lethal PG endopeptidases MepS and MepM, which are involved in PG synthesis. A mutant defective for both MepS and MepM was lethal in an amino acid-rich medium, whereas it exhibited almost normal growth in a minimal medium, suggesting the expendability of MepS and MepM in a minimal medium. Protein levels of MepS and MepM dramatically decreased in the minimal medium. Although MepM was revealed as a substrate of Prc, a periplasmic protease involved in the proteolysis of MepS, only the decrease in the MepS level in the minimal medium was affected by the prc depletion. Phenotypic and biochemical analyses showed that the presence of aromatic amino acids in the medium induced the accumulation of MepS, but not MepM, while the presence of glutamate increased the level of MepM, but not MepS. Together, these results demonstrate that the protein levels of the two major PG endopeptidases are regulated in an amino acid availability-dependent manner, but their molecular mechanisms and signaling are significantly distinct.


Physiology ◽  
2006 ◽  
Vol 21 (2) ◽  
pp. 115-123 ◽  
Author(s):  
Adriana Donovan ◽  
Cindy N. Roy ◽  
Nancy C. Andrews

Iron is an essential element that is toxic when it accumulates in excess. Intricate regulatory mechanisms have evolved to maintain iron homeostasis within cells and between different tissues of complex organisms. This review discusses the proteins involved in iron transport and storage and their regulation in health and disease.


1988 ◽  
Vol 51 (2) ◽  
pp. 103-109 ◽  
Author(s):  
Jennifer A. Marshall Graves ◽  
Garey W. Dawson

SummaryIn marsupials, X chromosome inactivation is paternal and incomplete. The tissue-specific pattern of inactivation of X-linked loci (G6PD, PGK, GLA) has been attributed to a piecemeal inactivation of different regions of the X. We here propose an alternative hypothesis, in which inactivation of the marsupial X is a chromosome-wide event, but is differentially regulated in different tissues. This hypothesis was suggested by the relationship between the positions and activity of genes on the kangaroo paternal X. In the absence of an HPRT polymorphism, we have used somatic cell hybridization to assess the activity of the paternal HPRT allele in lymphocytes and fibroblasts. The absence of the paternal X, and of the paternal forms of G6PD or PGK, from 33 cell hybrids made by fusing HPRT-deficient rodent cells with lymphocytes or fibroblasts of heterozygous females, suggests that the HPRT gene on the paternal X is inactive in both tissues and therefore not selectable. Since HPRT is located medially on the Xq near GLA, which shares the same characteristics of activity, we suggest that the locus-specific and tissue-specific patterns of activity result from a differential spread of inactivation from a single control locus, located near HPRT and GLA, outwards in both directions to G6PD and PGK. The nucleolus organizer region on the short arm does not seem to be part of the inactivated unit.


1993 ◽  
Vol 13 (4) ◽  
pp. 2564-2577 ◽  
Author(s):  
J C McDermott ◽  
M C Cardoso ◽  
Y T Yu ◽  
V Andres ◽  
D Leifer ◽  
...  

The myocyte enhancer-binding factor 2 (MEF2) site is an essential element of many muscle-specific enhancers and promoters that binds nuclear proteins from muscle and brain. Recently, we have cloned a family of MEF2 transcription factors produced by two genes that, at the mRNA level, are broadly expressed and produce tissue-specific isoforms by posttranscriptional processes (Y.-T. Yu, R. E. Breitbart, L. B. Smoot, Y. Lee, V. Mahdavi, and B. Nadal-Ginard, Genes Dev. 6:1783-1798, 1992). Here, we report the isolation and functional characterization of cDNA clones encoding four MEF2 factors derived from a separate gene that we have named hMEF2C. In contrast to those of the previously reported genes, the transcripts of the hMEF2C gene are restricted to skeletal muscle and brain. One of the alternate exons is exclusively present in brain transcripts. The products of this gene have DNA-binding and trans-activating activities indistinguishable from those of the previously reported MEF2 factors. The hMEF2C gene is induced late during myogenic differentiation, and its expression is limited to a subset of cortical neurons. The potential targets for this transcription factor in a subset of neurons are not known at this time. The strict tissue-specific pattern of expression of hMEF2C in comparison with the more ubiquitous expression of other MEF2 genes suggests a different mode of regulation and a potentially important role of hMEF2C factors in myogenesis and neurogenesis.


2018 ◽  
Vol 27 (16) ◽  
pp. 2851-2862 ◽  
Author(s):  
Ewout J N Groen ◽  
Elena Perenthaler ◽  
Natalie L Courtney ◽  
Crispin Y Jordan ◽  
Hannah K Shorrock ◽  
...  

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