Rqc1 and other yeast proteins containing highly positively charged sequences are not targets of the RQC complex.

Previous work has suggested that highly positively charged protein segments coded by rare codons or poly (A) stretches induce ribosome stalling and translational arrest through electrostatic interactions with the negatively charged ribosome exit tunnel, leading to inefficient elongation. This arrest leads to the activation of the Ribosome Quality Control (RQC) pathway and results in low expression of these reporter proteins. However, the only endogenous yeast proteins known to activate the RQC are Rqc1, a protein essential for RQC function, and Sdd1, a protein with unknown function, both of which contain polybasic sequences. To explore the generality of this phenomenon, we investigated whether the RQC complex controls the expression of other proteins with polybasic sequences. We showed by ribosome profiling data analysis and western blot that proteins containing polybasic sequences similar to, or even more positively charged than those of Rqc1 and Sdd1, were not targeted by the RQC complex. We also observed that the previously reported Ltn1-dependent regulation of Rqc1 is posttranslational, independent of the RQC activity. Taken together, our results suggest that RQC should not be regarded as a general regulatory pathway for the expression of highly positively charged proteins in yeast.

Protein charge distribution in proteomes and its impact on translation.

As proteins are synthesized, the nascent polypeptide must pass through a negatively charged exit tunnel. During this stage, positively charged stretches can interact with the ribosome walls and slow the translation. Therefore, charged polypeptides may be important factors that affect protein expression. To determine the frequency and distribution of positively and negatively charged stretches in different proteomes, the net charge was calculated for every 30 consecutive amino acid residues, which corresponds to the length of the ribosome exit tunnel. The following annotated and reviewed proteins in the UniProt database (Swiss-Prot) were analyzed: 551,705 proteins from different organisms and a total of 180 million protein segments. We observed that there were more negative than positive stretches and that super-charged positive sequences (i.e., net charges ≥ 14) were underrepresented in the proteomes. Overall, the proteins were more positively charged at their N-termini and C-termini, and this feature was present in most organisms and subcellular localizations. To investigate whether the N-terminal charges affect the elongation rates, previously published ribosomal profiling data obtained from S. cerevisiae, without translation-interfering drugs, were analyzed. We observed a nonlinear effect of the charge on the ribosome occupancy in which values ≥ +5 and ≤ -6 showed increased and reduced ribosome densities, respectively. These groups also showed different distributions across 80S monosomes and polysomes. Basic polypeptides are more common within short proteins that are translated by monosomes, whereas negative stretches are more abundant in polysome-translated proteins. These findings suggest that the nascent peptide charge impacts translation and can be one of the factors that regulate translation efficiency and protein expression.

Perícia psicológica no abuso sexual de crianças e adolescentes / Forensic psychological examination in child and adolescent sexual abuse

Ao mesmo tempo em que denúncias de abuso sexual contra crianças e adolescentes são frequentes, implicando em medidas protetivas urgentes para as vítimas e punições para os perpetradores, também são crescentes os casos de falsas denúncias. Este artigo tem como principal objetivo revisar, com base na literatura nacional e internacional recente, o papel da perícia psicológica no abuso sexual infantojuvenil. Na comum inexistência de vestígios físicos, uma avaliação psicológica abrangente demonstra-se imprescindível, devendo integrar diferentes fontes de informação e indicadores, já que alguns destes são contraditórios e inespecíficos. O perito deve possuir formação na área de atuação e conhecimentos sobre a legislação vigente, além de assegurar que a avaliação não se torne um elemento abusivo para o periciado.

At the same time that allegations of sexual abuse against children and adolescents are frequent, enhancing urgent protective measures for victims and punishment for the perpetrators, there is also an increasing frequency of void allegations. This paper aims to review, from recent national and international literature, the role of psychological examination in child and adolescent sexual abuse. The literature review shows that since lack of physical evidence is common, a wide psychological evaluation is essential, and must integrate different information sources and indicators, some of which are inconsistent and nonspecific. An expert must have extensive training in the field and knowledge of the current legislation, making sure that the evaluation will not turn out to be traumatic for the client.