An Allosteric Cross-Talk Between the Activation Loop and the ATP Binding Site Regulates the Activation of Src Kinase

Phosphorylation of the activation loop is a fundamental step in the activation of most protein kinases. In the case of the Src tyrosine kinase, a prototypical kinase due to its role in cancer and its historic importance, phosphorylation of tyrosine 416 in the activation loop is known to rigidify the structure and contribute to the switch from the inactive to a fully active form. However, whether or not phosphorylation is able per-se to induce a fully active conformation, that efficiently binds ATP and phosphorylates the substrate, is less clear. Here we employ a combination of solution NMR and enhanced-sampling molecular dynamics simulations to fully map the effects of phosphorylation and ATP/ADP cofactor loading on the conformational landscape of Src tyrosine kinase. We find that both phosphorylation and cofactor binding are needed to induce a fully active conformation. What is more, we find a complex interplay between the A-loop and the hinge motion where the phosphorylation of the activation-loop has a significant allosteric effect on the dynamics of the C-lobe

Corporate Social Responsibility Strategies of Spanish Listed Firms and Controlling Shareholders’ Representatives

This article aims at analyzing how controlling shareholders’ representatives on boards affect corporate social responsibility (CSR) strategies (disclosing CSR matters) in Spain, a context characterized by high ownership concentration, one-tier boards, little board independence, weak legal protection for investors, and the presence of large shareholders, especially institutional shareholders. Furthermore, among controlling shareholders’ representatives, we can distinguish between those appointed by insurance companies and banks and those appointed by mutual funds, investment funds, and pension funds. The effect of these categories of directors on CSR strategies is, therefore, also analyzed. Our findings suggest that controlling shareholders’ representatives have a positive effect on CSR strategies, as do directors appointed by investment funds, pension funds, and mutual funds, while directors appointed by banks and insurance companies have no impact on CSR strategies. This analysis offers new insights into the role played by certain types of directors on CSR strategies

Female Institutional Directors on Boards and Firm Value

The aim of this research is to examine what impact female institutional directors on boards have on corporate performance. Previous research shows that institutional female directors cannot be considered as a homogeneous group since they represent investors who may or may not maintain business relations with the companies on whose corporate boards they sit. Thus, it is not only the effect of female institutional directors as a whole on firm value that has been analysed, but also the impact of pressure-resistant female directors, who represent institutional investors (investment, pension and mutual funds) that only invest in the company, and do not maintain a business relation with the firm. We hypothesize that there is a non-linear association, specifically quadratic, between institutional and pressure-resistant female directors on boards and corporate performance. Our results report that female institutional directors on boards enhance corporate performance, but when they reach a certain threshold on boards (11.72 %), firm value decreases. In line with female institutional directors, pressure-resistant female directors on boards also increase firm value, but only up to a certain figure (12.71 % on boards), above which they have a negative impact on firm performance. These findings are consistent with an inverted U-shaped relationship between female institutional directors and pressure-resistant female directors and firm performance

Local coexistence and niche differences between the Lusitanian and Mediterranean pine voles (Microtus lusitanicus and M. duodecimcostatus)

In the present study, we analyzed the coexistence pattern of the Lusitanian pine vole (Microtus lusitanicus) and the Mediterranean pine vole (Microtus duodecimcostatus) in a potential area of sympatry in a Mediterranean landscape (Portugal). We also determined the relative contribution of local, landscape, and spatial factors explaining the differences in the distribution patterns of the two species in the region. Using a kriging interpolation method, we obtained a map of sympatric and allopatric areas of species occurrence. The estimated sympatry area corresponded to a north-west–southeast belt representing 11.3% of the study area. Habitat niche differences were assessed with binomial GLMs followed by a variance partitioning. At a local scale, higher altitude, higher cover of shrubs, lower clay content in the soil, and lower cover of tree canopy were the most important factors distinguishing M. lusitanicus presence sites from those with M. duodecimcostatus. At a larger scale, the presence of forest landscape units and the low abundance of ‘‘montado’’ units were the most influencing landscape factors in the identification of M. lusitanicus occurrence sites when compared to M. duodecimcostatus. Our results suggested that local coexistence of M. lusitanicus and M. duodecimcostatus in the field is a rare event. The differences in distribution patterns of the two pine vole species were mostly explained by fine-scale environmental factors and by shared spatial effects