No abstract

Protein complexes involved in respiration, ATP synthesis, and protein import reside in the mitochondrial inner membrane; thus, proper regulation of these proteins is essential for cell viability. The -AAA protease, a conserved hetero-hexameric AAA (ATPase associated with diverse cellular activities) protease, composed of the Yta10 and Yta12 proteins, regulates mitochondrial proteostasis by mediating protein maturation and degradation. It also recognizes and mediates the dislocation of membrane-embedded substrates, including foreign transmembrane (TM) segments, but the molecular mechanism involved in these processes remains elusive. This study investigated the role of the TM domains in the-AAA protease by systematic replacement of one TM domain at a time in yeast. Our data indicated that replacement of the Yta10 TM2 domain abolishes membrane dislocation for only a subset of substrates, whereas replacement of the Yta12 TM2 domain impairs membrane dislocation for all tested substrates, suggesting different roles of the TM domains in each -AAA protease subunit. Furthermore,-AAA protease-mediated membrane dislocation was impaired in the presence of a large downstream hydrophilic moiety in a membrane substrate. This finding suggested that the -AAA protease cannot dislocate large hydrophilic domains across the membrane, indicating that the membrane dislocation probably occurs in a lipid environment. In summary, this study highlights previously underappreciated biological roles of TM domains of the-AAA proteases in mediating the recognition and dislocation of membrane-embedded substrates.

The TIM23 complex mediates membrane insertion of presequence‐containing mitochondrial proteins via a stop‐transfer mechanism. Stop‐transfer signals consist of hydrophobic transmembrane segments and flanking charges. Mgr2 functions as a lateral gatekeeper of the TIM23 complex. However, it remains elusive which features of stop‐transfer signals are discriminated by Mgr2. To determine the effects of Mgr2 on the TIM23‐mediated stop‐transfer pathway, we measured membrane insertion of model transmembrane segments of varied hydrophobicity and flanking charges in Mgr2‐deletion or ‐overexpression yeast strains. We found that upon deletion of Mgr2, the threshold hydrophobicity for membrane insertion, as well as the requirement for matrix‐facing positive charges, is reduced. These results imply that the Mgr2‐mediated gatekeeper function is important for controlling membrane sorting of marginal stop‐transfer signals.

The goal of this study is to evaluate the effectiveness of youth volunteering in increasing the self-esteem of hearing children of deaf adults (CODAs), who commonly start taking care of their parents from a young age. To this end, an experimental study based on the non-equal comparison groups design was applied to a experimental group of 4 participants and a control group of 3 participants, selected based on the recommendation from expert social workers from the M General Social Welfare Center in P City. The volunteer programs, conducted non-face-to-face due to COVID-19, were centered on art activities such as drawing one's own dreams, decorating flowers, and customizing pencil cases. Repeated measures analysis of variance (rANOVA) was conducted to verify the effectiveness of volunteering, and the analysis results are as follows. First, in both the experimental group and the control group, CODAs’ self esteem increased after the program was carried out. Second, while the growth effect appeared in both groups, the slope of increase in the self-esteem of the experimental group was significantly higher than that of the control group. Accordingly, the effectiveness of volunteering to improve CODAs' self-esteem was verified. This study suggests academic and practical implications based on these findings.

The empirical examples of the green-beard genes, once a conundrum of evolutionary biology, are accumulating, while theoretical analyses of this topic are occasional compared to those concerning (narrow-sense) kin selection. In particular, the recognition error of the green-beard effect that the cooperator fails to accurately recognize the other cooperators or defectors is readily found in numerous green-beard genes. To our knowledge, however, no model up to date has taken that effect into account. In this article, we investigated the effect of recognition error on the fitness of the green-beard gene. By employing theories of evolutionary games, our mathematical model predicts that the fitness of the green-beard gene is frequency dependent (frequency of the green-beard gene), which was corroborated by experiments performed with yeast FLO1. The experiment also shows that the cells with the green-beard gene (FLO1) are sturdier under severe stress. We conclude that the low recognition error among the cooperators, the higher reward of cooperation, and the higher cost of defection confer an advantage to the green-beard gene under certain conditions, confirmed by numerical simulation as well. Interestingly, we expect that the recognition error to the defectors may promote the cooperator fitness if the cooperator frequency is low and mutual defection is detrimental. Our ternary approach of mathematical analysis, experiments, and simulation lays the groundwork of the standard model for the green-beard gene that can be generalized to other species.

This protocol describes how to stain Brown Adipose Tissue using iDisco protocol and visualize the result via confocal microscope.

No abstract

This protocol describes how to retrogradely label the Brown Adipose Tissue (BAT) - projecting sympathetic neruons in stellate ganglia (SG) using Cholera toxin subunit B (CTB) conjugated with Alexa Flour 555.