H1 and HMGB1: modulators of chromatin structure

2012 ◽  
Vol 40 (2) ◽  
pp. 341-346 ◽  
Author(s):  
Jean O. Thomas ◽  
Katherine Stott
Keyword(s):  
Chromatin Structure ◽  
High Mobility ◽  
Stable Structure ◽  
Dynamic Nature ◽  
High Mobility Group Protein ◽  
Chromosomal Proteins ◽  
Core Histones ◽  
Group Protein

Histone H1 and HMGB1 (high-mobility group protein B1) are the most abundant chromosomal proteins apart from the core histones (on average, one copy per nucleosome and per ten nucleosomes respectively). They are both highly mobile in the cell nucleus, with high on/off rates for binding. In vivo and in vitro evidence shows that both are able to organize chromatin structure, with H1 binding resulting in a more stable structure and HMGB1 binding in a less stable structure. The binding sites for H1 and HMGB1 in chromatin are partially overlapping, and replacement of H1 by HMGB1 through the highly dynamic nature of their binding, possibly facilitated by interaction between them, could result in switching of chromatin states. Binding of HMGB1 to DNA or chromatin is regulated by its long and highly acidic tail, which is also involved in H1 binding. The present article focuses mainly on HMGB1 and its interaction with chromatin and H1, as well as its chaperone role in the binding of certain transcription factors (e.g. p53) to their cognate DNA.

scholarly journals Knockdown of MSI2 inhibits metastasis by interacting with caveolin-1 and inhibiting its ubiquitylation in human NF1-MPNST cells

2020 ◽  
Vol 11 (6) ◽  
Author(s):  
Kang Yang ◽  
Jianwei Du ◽  
Dai Shi ◽  
Feng Ji ◽  
Yong Ji ◽  
...  
Keyword(s):  
Epithelial Mesenchymal Transition ◽  
High Mobility ◽  
Neurofibromatosis Type ◽  
Migration And Invasion ◽  
High Mobility Group Protein ◽  
Mesenchymal Transition ◽  
Caveolin 1 ◽  
Group Protein

AbstractMalignant peripheral nerve sheath tumours (MPNSTs) are highly aggressive Schwann cell-derived sarcomas, and they are either associated with neurofibromatosis type 1 (NF1) or sporadic. Our previous study found that high mobility group protein A2 (HMGA2) regulates NF1-MPNST growth through Musashi-2 (MSI2); however, whether MSI2 regulates MPNST metastasis and what the mechanism is remain unclear. Here, we demonstrated that the protein caveolin-1 (CAV1) directly interacts with MSI2 in human NF1-MPNST cells. Moreover, we discovered that knockdown of MSI2 induces CAV1 protein expression by inhibiting its ubiquitylation level in NF1-MPNSTs. In addition, CAV1 mediates the suppressive function of MSI2 in epithelial-mesenchymal transition, migration and invasion in vitro and metastasis in vivo. These results help to reveal the potential mechanisms of MSI2 as a target of antimetastatic treatment for human NF1-MPNST.

Preferential Phosphorylation of High Mobility Group Protein 17 in vitro by a Nuclear Protein Kinase

1981 ◽  
Vol 36 (3-4) ◽  
pp. 319-322 ◽  
Keyword(s):  
Nuclear Protein ◽  
High Mobility ◽  
High Specificity ◽  
High Mobility Group ◽  
Hmg Proteins ◽  
High Mobility Group Protein ◽  
High Preference ◽  
Group Protein

The ability of the high mobility group proteins (HMG-1,2,14 and 17) to serve as substrate for protein kinases was investigated by incubating them with a cytoplasmic and nuclear kinase. In both cases phosphate was incorporated into all four HMG proteins. The amount of phosphate incorporated and the specificity for the four proteins was quite different for the two kinases. Whereas the cytoplasmic kinase phosphorylated the HMG-1 and 2 to a higher degree than HMG-14 and 17, the nuclear kinase exhibited a high specificity for the HMG -17, leaving the other three proteins with only a small amount. The high preference of a nuclear kinase for HMG-17 may be indicative of a specific phosphorylation occuring also in vivo

scholarly journals Distinct functional properties of IkappaB alpha and IkappaB beta.

1997 ◽  
Vol 17 (9) ◽  
pp. 5386-5399 ◽  
Author(s):  
K Tran ◽  
M Merika ◽  
D Thanos
Keyword(s):  
Transcriptional Activation ◽  
High Mobility ◽  
In Vitro Transcription ◽  
Binding Activity ◽  
High Mobility Group Protein ◽  
Dna Binding Activity ◽  
Group Protein ◽  
Nf Kappab

The biological activity of the transcription factor NF-kappaB is controlled mainly by the IkappaB alpha and IkappaB beta proteins, which restrict NF-kappaB to the cytoplasm and inhibit its DNA binding activity. Here, we carried out experiments to determine and compare the mechanisms by which IkappaB alpha and IkappaB beta inhibit NF-kappaB-dependent transcriptional activation. First, we found that in vivo IkappaB alpha is a stronger inhibitor of NF-kappaB than is IkappaB beta. This difference is directly correlated with their abilities to inhibit NF-kappaB binding to DNA in vitro and in vivo. Moreover, IkappaB alpha, but not IkappaB beta, can remove NF-kappaB from functional preinitiation complexes in in vitro transcription experiments. Second, we showed that both IkappaBs function in vivo not only in the cytoplasm but also in the nucleus, where they inhibit NF-kappaB binding to DNA. Third, the inhibitory activity of IkappaB beta, but not that of IkappaB alpha, is facilitated by phosphorylation of the C-terminal PEST sequence by casein kinase II and/or by the interaction of NF-kappaB with high-mobility group protein I (HMG I) on selected promoters. The unphosphorylated form of IkappaB beta forms stable ternary complexes with NF-kappaB on the DNA either in vitro or in vivo. These experiments suggest that IkappaB alpha works as a postinduction repressor of NF-kappaB independently of HMG I, whereas IkappaB beta functions preferentially in promoters regulated by the NF-kappaB/HMG I complexes.

scholarly journals The RAG1 Homeodomain Recruits HMG1 and HMG2 To Facilitate Recombination Signal Sequence Binding and To Enhance the Intrinsic DNA-Bending Activity of RAG1-RAG2

1999 ◽  
Vol 19 (10) ◽  
pp. 6532-6542 ◽  
Author(s):  
Vassilis Aidinis ◽  
Tiziana Bonaldi ◽  
Monica Beltrame ◽  
Sandro Santagata ◽  
Marco E. Bianchi ◽  
...  
Keyword(s):  
Signal Sequence ◽  
Specific Binding ◽  
High Mobility ◽  
Recombination Reaction ◽  
High Mobility Group Protein ◽  
Bent Dna ◽  
Recombination Signal ◽  
Group Protein

ABSTRACT V(D)J recombination is initiated by the specific binding of the RAG1-RAG2 (RAG1/2) complex to the heptamer-nonamer recombination signal sequences (RSS). Several steps of the V(D)J recombination reaction can be reconstituted in vitro with only RAG1/2 plus the high-mobility-group protein HMG1 or HMG2. Here we show that the RAG1 homeodomain directly interacts with both HMG boxes of HMG1 and HMG2 (HMG1,2). This interaction facilitates the binding of RAG1/2 to the RSS, mainly by promoting high-affinity binding to the nonamer motif. Using circular-permutation assays, we found that the RAG1/2 complex bends the RSS DNA between the heptamer and nonamer motifs. HMG1,2 significantly enhance the binding and bending of the 23RSS but are not essential for the formation of a bent DNA intermediate on the 12RSS. A transient increase of HMG1,2 concentration in transfected cells increases the production of the final V(D)J recombinants in vivo.

The High Mobility Group Protein HMGA2: A Co-Regulator of Chromatin Structure and Pluripotency in Stem Cells?

2009 ◽  
Vol 5 (3) ◽  
pp. 224-230 ◽  
Author(s):  
Kurt Pfannkuche ◽  
Heike Summer ◽  
Ou Li ◽  
Jürgen Hescheler ◽  
Peter Dröge
Keyword(s):  
Stem Cells ◽  
Chromatin Structure ◽  
High Mobility ◽  
High Mobility Group ◽  
High Mobility Group Protein ◽  
Group Protein

scholarly journals Changes in quantities of high-mobility-group protein 1 in oviduct cellular fractions after oestrogen stimulation

1981 ◽  
Vol 198 (1) ◽  
pp. 85-90 ◽  
Author(s):  
C T Teng ◽  
C S Teng
Keyword(s):  
Microsomal Fraction ◽  
High Mobility ◽  
Quantitative Change ◽  
High Mobility Group ◽  
Nuclear Fraction ◽  
Hmg Proteins ◽  
High Mobility Group Protein ◽  
Group Protein ◽  
Oviduct Cell

Antiserum against chick oviduct high-mobility-group protein 1 (HMG 1) has been induced in the rabbit. With this antiserum, immunobiochemical techniques have been used to probe the quantitative change of HMG 1 in the cellular fractions of chick oviduct before or after oestrogen stimulation. HMG 1 is detectable in the cytosol, microsomal and nuclear fraction of the chick oviduct cell. After administration of oestrogen to young chicks in vivo for 5 days, the quantity of HMG 1 is increased 4-fold in the cytosol, 3.5-fold in the microsomal fraction and 1.6-fold in the nuclear fraction. The finding of large amounts of HMG 1 in cytoplasm of oviduct cell is not likely due to its leakage from the nucleus. We anticipate that HMG 1 is synthesized in the cytoplasm and then transported into the nucleus. The synthesis and transportation of HMG proteins is probably regulated by oestrogen.

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