Protein design studies using coiled coils have illustrated the potential of engineering simple peptides to self-associate into polymers and networks. Although basic aspects of self-assembly in protein systems have been demonstrated, it remains a major challenge to create materials whose large-scale structures are well determined from design of local protein-protein interactions. Here, we show the design and characterization of a helical peptide, which uses phased hydrophobic interactions to drive assembly into nanofilaments and fibrils (''nanoropes''). Using the hydrophobic effect to drive self-assembly circumvents problems of uncontrolled self-assembly seen in previous approaches that used electrostatics as a mode for self-assembly. The nanostructures designed here are characterized by biophysical methods including analytical ultracentrifugation, dynamic light scattering, and circular dichroism to measure their solution properties, and atomic force microscopy to study their behavior on surfaces. Additionally, the assembly of such structures can be predictably regulated by using various environmental factors, such as pH, salt, other molecular crowding reagents, and specifically designed ''capping'' peptides. This ability to regulate self-assembly is a critical feature in creating smart peptide biomaterials.biomaterial ͉ coiled coil ͉ protein design ͉ circular dichroism ͉ atomic force microscopy D esigned proteins are valuable paradigms for engineering at the nanoscale, offering favorable properties such as atomiclevel precision and tight regulation of self-assembly by using a variety of environmental cues (i.e., pH, ionic strength, temperature) (1-3). As one of the most well studied and naturally abundant structural motifs in proteins, coiled coils are particularly suited to protein design. Their basic sequence feature, the heptad repeat, is a seven-residue pattern (abcdefg) n of nonpolar and polar residues that gives rise to amphipathic ␣-helices. The hydrophobic effect drives the burial of nonpolar residues at the helix-pairing interface and influences geometric details of resulting structures (4). Electrostatic and polar residues at buried or solvent-exposed locations provide additional means to manipulate structural features by stabilization or destabilization (negative design) of key interactions (5-8).Recent attempts to design self-assembling protein networks by using coiled coils have focused on simple systems, such as linear and branched fibrils (9-14), planar assemblies (15), and hydrogels (16-18). Specifically, filament formation has been achieved by stabilization of intermediate structures that foster intermolecular coiled-coil interactions (11)(12)(13)(14). Previous studies have reported the design of short helical peptides, which interact via a dimeric coiled-coil motif and are stabilized by a combination of overlapping hydrophobic and electrostatic intermolecular interactions (9, 13, 14). These peptides do indeed self-assemble into filaments; however, these filaments also show evidence of extensive...

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Employee voice behavior has attained significant attention in contemporary research due to its positive consequences for both workers and employers. Drawing on the social exchange theory, this study examined the mediating role of job satisfaction and psychological empowerment on the relationship between transformational leadership and employee’s voice behavior. Data were collected through survey questionnaires by utilizing a three-wave time-lagged study design from employees from diverse private and public sector organizations in Pakistan. The parallel multiple mediation is tested through Hayes’s process macro. The results indicate that job satisfaction and psychological empowerment partially mediate the relationship between transformational leadership and employee’s voice behavior. Further analysis depicts that both job satisfaction and psychological empowerment leveraged under transformational leadership act as parallel mediators and have no statistical significant difference between them. The theoretical and managerial implications are discussed.

Organizations in the era of globalization are promoting managerial coaching (MC) as human resource development practice to improve employees' outcomes in the workplace. The existing literature on manager coaching lacks the empirical studies showing the linking MC with attitudes and behaviors of employees. To fill the gap mentioned above, this study explores the direct linkage between the MC and innovative work behaviors (IWBs) of employees as well as an indirect relationship through the intervening role of affective supervisory commitment (ASC). The 250 surveys were sent to employees working in the software industry of Pakistan, and 207 questionnaires were received back from the respondents, and the response rate was approximately 83%. The findings showed that MC had a positive influence on IWBs among employees. Results also showed that ASC mediated the link between MC and IWBs. ASC as a mediator has not been tested yet between the linkage of MC with IWBs. The implications of the study and limitations are also discussed.

Effects of IFN-gamma on mammalian small intestinal ion transport were studied in vitro using incubated sheets of murine small intestine in Ussing chambers. In oxygenated standard culture medium containing hydrocortisone and antibiotics, they maintained their short-circuit current (I(sc)) responses to glucose and theophylline for 48 h. Histological examination revealed a 50% diminution of villus height over 36 h but no change in crypts. Height was better maintained during a 36-h incubation of small intestine from SCID mice, suggesting a role for B or T lymphocytes in villus atrophy. Exposure of small intestine to 100 U/ml IFN-gamma for 36 h decreased basal I(sc) by 40% and I(sc) responses to glucose and theophylline by approximately 70%; at 1,000 U/ml for 36 h, IFN-gamma inhibited these I(sc) responses by 90%. An inhibitor of inducible NO synthase did not reverse these effects, suggesting that they are not mediated by NO. Tissue resistance, mucosal K(+) content, and epithelial morphology were not affected. Ouabain-sensitive ATPase activity in homogenates was inhibited 60% by IFN-gamma (100 U/ml for 36 h). IFN-gamma inhibition of I(sc) responses to glucose and theophylline also occurred in SCID mouse small intestine. Thus murine small intestinal sheets can be maintained viable in vitro for at least 48 h, although villus blunting develops (but less so in SCID mouse small intestine). Also, prolonged exposure to IFN-gamma downregulates Na(+)-coupled glucose absorption, active Cl(-) secretion, and Na(+)-K(+)-ATPase activity, effects unlikely to be mediated by enhanced NO.

Background Runt related transcription factor3 (RUNX3) is considered as a tumor suppressor gene (TSG) that functions through the TGF-β dependent apoptosis. Promoter methylation of the CpG islands of RUNX3 and overexpression of enhancer of zeste homolog 2 (EZH2) has been suggested to downregulate RUNX3 in cancer. Methods Here, we studied the expression of RUNX3 and EZH2 in 58 esophageal tumors along with paired adjacent normal tissue. mRNA levels, protein expressions and cellular localizations of EZH2 and RUNX3 were analyzed using real-time PCR and immunohistochemistry, respectively. DNA methylation was further assessed by the methylation specific-PCR. Results Compared to normal tissue, a significant increase in expression of RUNX3 mRNA in 31/57 patient’s tumor tissue (p < 0.04) was observed. The expression of EZH2 was found to be upregulated compared to normal, and a significant positive correlation between EZH2 and RUNX3 expression was observed (p = 0.002). 22 of the 27 unmethylated cases at the promoter region of the RUNX3 had elevated RUNX3 protein expression (p < 0.001). Conclusion The data presented in this study provide new insights into the biology of RUNX3 and highlights the need to revisit our current understanding of the role of RUNX3 in cancer.

This study investigates how perceived corporate social responsibility directly influence the job satisfaction and organizational citizenship behavior of employees, and indirectly influence through the mediating effect work engagement. A questionnaire-based survey was conducted to collect data from 327 students of MBA executive employed in different organizations of Lahore, Pakistan. Structural equation modeling was applied to test the hypothesized conceptual model. Results reveal that corporate social responsibility activities of the organizations increase job satisfaction and discretionary behaviors or organizational citizenship behavior among employees. CSR also increases work engagement, which, in turn, increases job satisfaction and organizational citizenship behavior as well. This study has shown that concerns toward CSR have increased in the business organization operating in developing countries, and employees working in those organizations are reciprocating to CSR through positive outcomes in the workplace. The employees, as internal stakeholders are responding favorably to the CSR. As per the best of researchers' knowledge, the study firstly tests the mediating role of work engagement in the linkage of CSR with job satisfaction and organizational citizenship behavior. The theoretical and practical implications are also discussed.