The structure of an LIM-only protein 4 (LMO4) and deformed epidermal autoregulatory factor-1 (DEAF1) complex reveals a common mode of binding to LMO4

LIM-domain only protein 4 (LMO4) is a widely expressed protein with important roles in embryonic development and breast cancer. It has been reported to bind many partners, including the transcription factor Deformed epidermal autoregulatory factor-1 (DEAF1), with which LMO4 shares many biological parallels. We used yeast two-hybrid assays to show that DEAF1 binds both LIM domains of LMO4 and that DEAF1 binds the same face on LMO4 as two other LMO4-binding partners, namely LIM domain binding protein 1 (LDB1) and C-terminal binding protein interacting protein (CtIP/RBBP8). Mutagenic screening analysed by the same method, indicates that the key residues in the interaction lie in LMO4LIM2 and the N-terminal half of the LMO4-binding domain in DEAF1. We generated a stable LMO4LIM2-DEAF1 complex and determined the solution structure of that complex. Although the LMO4-binding domain from DEAF1 is intrinsically disordered, it becomes structured on binding. The structure confirms that LDB1, CtIP and DEAF1 all bind to the same face on LMO4. LMO4 appears to form a hub in protein-protein interaction networks, linking numerous pathways within cells. Competitive binding for LMO4 therefore most likely provides a level of regulation between those different pathways.SJ was funded by an Australian Postgraduate Award (education.gov.au/australian-postgraduate-awards). JPM and JMM were awarded Senior Research Fellowships from the Australian National and Medical Research Council (www.nhmrc.gov.au). This project was funded by an Australian Research Council (www. arc.gov.au) Discovery Project Grant (DP110104332) to JMM and LC

Politicians, Pundits, and Platform Migration: A Comparison of Political Polarization on Parler and Twitter

Parler, a self-proclaimed free speech social media platform founded in 2018, attracted a large influx of new members in 2020 as the result of a highly visible platform migration campaign. Parler usage was linked to the planning of the Jan. 6, 2021 attack on the United States Capitol building, leading to a shutdown of the Parler platform. Parler, which is now back online, offers an important lens through which to examine the broader attempts at platform migration in response to changing content moderation and platform governance policies and their impact on political polarization. We begin by examining the network connections between US Congressional Representatives on both Twitter and Parler. We find that Parler has a homogenous population of users, consisting of a single isolated group, where polarization seems irrelevant, while Twitter demonstrates two clearly polarized groups. We compare how politicians and political pundits use Parler differently. Finally, we examine the evolution of Parler including comparing Parler’s own policies before and after the shutdown and reflecting on the future of platforms like Parler and similar platform migration experiments

Comparing Sex Buyers With Men Who Do Not Buy Sex: New Data on Prostitution and Trafficking.

We investigated attitudes and behaviors associated with prostitution and sexual aggression among 101 men who buy sex and 101 age-, education-, and ethnicity-matched men who did not buy sex. Both groups tended to accept rape myths, be aware of harms of prostitution and trafficking, express ambivalence about the nature of prostitution, and believe that jail time and public exposure are the most effective deterrents to buying sex. Sex buyers were more likely than men who did not buy sex to report sexual aggression and likelihood to rape. Men who bought sex scored higher on measures of impersonal sex and hostile masculinity and had less empathy for prostituted women, viewing them as intrinsically different from other women. When compared with non-sex-buyers, these findings indicate that men who buy sex share certain key characteristics with men at risk of committing sexual aggression as documented by research based on the leading scientific model of the characteristics of non-criminal sexually aggressive men, the Confluence Model of sexual aggression

DNA-binding, multivalent interactions and phase separation in transcriptional activation

Transcription is an essential process in biology whereby gene-specific transcription factors target sites on DNA to recruit the basal transcription machinery that will produce messenger RNA (mRNA). It is a highly regulated multi-step process that involves many proteins and protein complexes. Transcription factors, the proteins that mark genes for activation, and other transcriptional regulators are highly enriched in low-complexity disordered regions, which are strongly linked to multivalent binding and phase separation. These disordered regions can form multivalent dynamic complexes that are essential for many aspects of transcription. Many of these proteins can phase separate in vitro and show evidence of phase separation in vivo. Whether these interactions represent biologically relevant phase separation in vivo is controversial. However, what these events do demonstrate is that many transcriptional proteins co-cluster with other factors in vivo, forming multivalent dynamic clusters that contribute to transcriptional events. We review some of these recently investigated events and consider how they contribute to our understanding of transcription

Projecting the effect of crop yield increases, dietary change and different price scenarios on land use under two different state security regimes

Peer reviewedPublisher PD

Grb7 SH2 domain structure and interactions with a cyclic peptide inhibitor of cancer cell migration and proliferation

<p>Abstract</p> <p>Background</p> <p>Human growth factor receptor bound protein 7 (Grb7) is an adapter protein that mediates the coupling of tyrosine kinases with their downstream signaling pathways. Grb7 is frequently overexpressed in invasive and metastatic human cancers and is implicated in cancer progression via its interaction with the ErbB2 receptor and focal adhesion kinase (FAK) that play critical roles in cell proliferation and migration. It is thus a prime target for the development of novel anti-cancer therapies. Recently, an inhibitory peptide (G7-18NATE) has been developed which binds specifically to the Grb7 SH2 domain and is able to attenuate cancer cell proliferation and migration in various cancer cell lines.</p> <p>Results</p> <p>As a first step towards understanding how Grb7 may be inhibited by G7-18NATE, we solved the crystal structure of the Grb7 SH2 domain to 2.1 Å resolution. We describe the details of the peptide binding site underlying target specificity, as well as the dimer interface of Grb 7 SH2. Dimer formation of Grb7 was determined to be in the μM range using analytical ultracentrifugation for both full-length Grb7 and the SH2 domain alone, suggesting the SH2 domain forms the basis of a physiological dimer. ITC measurements of the interaction of the G7-18NATE peptide with the Grb7 SH2 domain revealed that it binds with a binding affinity of K_d= ~35.7 μM and NMR spectroscopy titration experiments revealed that peptide binding causes perturbations to both the ligand binding surface of the Grb7 SH2 domain as well as to the dimer interface, suggesting that dimerisation of Grb7 is impacted on by peptide binding.</p> <p>Conclusion</p> <p>Together the data allow us to propose a model of the Grb7 SH2 domain/G7-18NATE interaction and to rationalize the basis for the observed binding specificity and affinity. We propose that the current study will assist with the development of second generation Grb7 SH2 domain inhibitors, potentially leading to novel inhibitors of cancer cell migration and invasion.</p

Characterisation of the pathogenic effects of the in vivo expression of an ALS-linked mutation in D-amino acid oxidase: Phenotype and loss of spinal cord motor neurons

Amyotrophic lateral sclerosis (ALS) is the most common adult-onset neuromuscular disorder characterised by selective loss of motor neurons leading to fatal paralysis. Current therapeutic approaches are limited in their effectiveness. Substantial advances in understanding ALS disease mechanisms has come from the identification of pathogenic mutations in dominantly inherited familial ALS (FALS). We previously reported a coding mutation in D-amino acid oxidase (DAOR199W) associated with FALS. DAO metabolises D-serine, an essential co-agonist at the N-Methyl-D-aspartic acid glutamate receptor subtype (NMDAR). Using primary motor neuron cultures or motor neuron cell lines we demonstrated that expression of DAOR199W, promoted the formation of ubiquitinated protein aggregates, activated autophagy and increased apoptosis. The aim of this study was to characterise the effects of DAOR199W in vivo, using transgenic mice overexpressing DAOR199W. Marked abnormal motor features, e.g. kyphosis, were evident in mice expressing DAOR199W, which were associated with a significant loss (19%) of lumbar spinal cord motor neurons, analysed at 14 months. When separated by gender, this effect was greater in females (26%; p< 0.0132). In addition, we crossed the DAOR199W transgenic mouse line with the SOD1G93A mouse model of ALS to determine whether the effects of SOD1G93A were potentiated in the double transgenic line (DAOR199W/SOD1G93A). Although overall survival was not affected, onset of neurological signs was significantly earlier in female double transgenic animals than their female SOD1G93A littermates (125 days vs 131 days, P = 0.0239). In summary, some significant in vivo effects of DAOR199W on motor neuron function (i.e. kyphosis and loss of motor neurons) were detected which were most marked in females and could contribute to the earlier onset of neurological signs in double transgenic females compared to SOD1G93A littermates, highlighting the importance of recognizing gender effects present in animal models of ALS