The Politics of Welfare Exclusion: Immigration and Disparity in Medicaid Coverage

The rapid growth of the immigrant population in the U.S., along with changes in the demographics and the political landscape, has often raised questions for understanding trends of inequality. Important issues that have received little scholarly attention thus far are excluding immigrants’ social rights through decisive policy choices and the distributive consequences of such exclusive policies. In this paper, we examine how immigration and state policies on immigrants’ access to safety net programs together influence social inequality in the context of health care. We analyze the combined effect of immigration population density and state immigrant Medicaid eligibility rules on the gap of Medicaid coverage rates between native- and foreign-born populations. When tracking inequality in Medicaid coverage and critical policy changes in the post-PRWORA era, we find that exclusive state policies widen the native-foreign Medicaid coverage gap. Moreover, the effect of state policies is conditional upon the size of the immigrant population in that state. Our findings suggest immigrants’ formal integration into the welfare system is crucial for understanding social inequality in the U.S. states

Structural Insights into the Inhibition of Actin-Capping Protein by Interactions with Phosphatidic Acid and Phosphatidylinositol (4,5)-Bisphosphate.

The actin cytoskeleton is a dynamic structure that coordinates numerous fundamental processes in eukaryotic cells. Dozens of actin-binding proteins are known to be involved in the regulation of actin filament organization or turnover and many of these are stimulus-response regulators of phospholipid signaling. One of these proteins is the heterodimeric actin-capping protein (CP) which binds the barbed end of actin filaments with high affinity and inhibits both addition and loss of actin monomers at this end. The ability of CP to bind filaments is regulated by signaling phospholipids, which inhibit the activity of CP; however, the exact mechanism of this regulation and the residues on CP responsible for lipid interactions is not fully resolved. Here, we focus on the interaction of CP with two signaling phospholipids, phosphatidic acid (PA) and phosphatidylinositol (4,5)-bisphosphate (PIP2). Using different methods of computational biology such as homology modeling, molecular docking and coarse-grained molecular dynamics, we uncovered specific modes of high affinity interaction between membranes containing PA/phosphatidylcholine (PC) and plant CP, as well as between PIP2/PC and animal CP. In particular, we identified differences in the binding of membrane lipids by animal and plant CP, explaining previously published experimental results. Furthermore, we pinpoint the critical importance of the C-terminal part of plant CPα subunit for CP–membrane interactions. We prepared a GST-fusion protein for the C-terminal domain of plant α subunit and verified this hypothesis with lipid-binding assays in vitro

Transient Gene Expression as a Tool to Monitor and Manipulate the Levels of Acidic Phospholipids in Plant Cells

Anionic phospholipids represent only minor fraction of cell membranes lipids but they are critically important for many membrane-related processes, including membrane identity, charge, shape, the generation of second messengers and the recruitment of peripheral proteins. The main anionic phospholipids of the plasma membrane are phosphoinositides phosphatidylinositol 4-phosphate (PI4P), phosphatidylinositol 4,5-bisphosphate (PI4,5P 2), phosphatidylserine (PS), and phosphatidic acid (PA). Recent insights in the understanding of the nature of protein-phospholipid interactions enabled the design of genetically-encoded fluorescent molecular probes that can interact with various phospholipids in a specific manner allowing their imaging in live cells. Here, we describe the use of transiently transformed plant cells to study phospholipid-dependent membrane recruitment

Arabidopsis capping protein senses cellular phosphatidic acid levels and transduces these into changes in actin cytoskeleton dynamics.

Addendum to: J Li, JL Henty-Ridilla, S Huang, X Wang, L Blanchoin, CJ Staiger. Capping protein modulates the dynamic behavior of actin filaments in response to phosphatidic acid in Arabidopsis.. Plant Cell 2012; 24:International audiencePlants respond rapidly and precisely to a broad spectrum of developmental, biotic and abiotic cues. In many instances, signaling cascades involved in transducing this information result in changes to the cellular architecture and cytoskeletal rearrangements. Based originally on paradigms for animal cell signaling, phospholipids have received increased scrutiny as key intermediates for transmitting information to the actin cytoskeleton. Significantly, a wealth of biochemical data for plant actin-binding proteins (ABPs) demonstrates that many of these interact with phosphoinositide lipids in vitro. Moreover, phosphatidic acid (PA) has been identified not only as an abundant structural lipid in plants, but also as an intermediary in developmental and stress signaling pathways that lead to altered actin organization. Several years ago, the heterodimeric capping protein (CP) from Arabidopsis was demonstrated to bind PA and is negatively regulated by this lipid in vitro. Whether this form of regulation occurs in cells, however, remained a mystery. A new study, that combines live-cell imaging of cytoskeletal dynamics with reverse-genetic analyses in Arabidopsis, provides compelling new evidence that CP is inhibited from binding filament ends in the presence of PA in vivo. This allows rapid actin polymerization and increases in filament abundance following stimulation and could be one key factor in the physiological responses of plant cells to environmental stimuli

The plant non-specific phospholipase C gene family. Novel competitors in lipid signalling

International audienceNon-specific phospholipases C (NPCs) were discovered as a novel type of plant phospholipid-cleaving enzyme homologous to bacterial phosphatidylcholine-specific phospholipases C and responsible for lipid conversion during phosphate-limiting conditions. The six-gene family was established in Arabidopsis, and growing evidence suggests the involvement of two articles NPCs in biotic and abiotic stress responses as well as phytohormone actions. In addition, the diacylglycerol produced via NPCs is postulated to participate in membrane remodelling, general lipid metabolism and cross-talk with other phospholipid signalling systems in plants. This review summarises information concerning this new plant protein family and focusses on its sequence analysis, biochemical properties, cellular and tissue distribution and physiological functions. Possible modes of action are also discussed

The economic contribution of humanitarian settlers in Australia

Article first published online: 25 APR 2013This article assesses the economic role of refugee settlers in Australia. Refugee-humanitarian labour force participation rates are lower than for other migrant groups or the Australia-born. However, their labour market performance converges toward that of the Australia-born over time. Moreover, the second generation performs at a higher level. There are a number of significant impediments to participation including language, education, structural disadvantage and discrimination. Indeed, there is evidence of a significant refugee gap which can only be explained by discrimination. It is shown that refugees represent a significant stock of human capital that is not being fully realized. They suffer more than other groups through non-recognition and there is substantial “brain waste” with negative results for the economy and the migrants themselves. Finally, it is shown that refugee-humanitarian settlers show greater propensity to form their own business than other migrants and that risk-taking, entrepreneurialism and an ability to identify and take advantage of opportunities is a key characteristic of the group.Graeme Hug

A Combinatorial Lipid Code Shapes the Electrostatic Landscape of Plant Endomembranes

International audienceMembrane surface charge is critical for the transient, yet specific recruitment of proteins with polybasic regions to certain organelles. In eukaryotes, the plasma membrane (PM) is the most electronegative compartment of the cell, which specifies its identity. As such, membrane electrostatics is a central parameter in signaling, intracellular trafficking, and polarity. Here, we explore which are the lipids that control membrane electrostatics using plants as a model. We show that phosphatidylinositol-4-phosphate (PI4P), phosphatidic acidic (PA), and phosphatidylserine (PS) are separately required to generate the electrostatic signature of the plant PM. In addition, we reveal the existence of an electrostatic territory that is organized as a gradient along the endocytic pathway and is controlled by PS/PI4P combination. Altogether, we propose that combinatorial lipid composition of the cytosolic leaflet of organelles not only defines the electrostatic territory but also distinguishes different functional compartments within this territory by specifying their varying surface charges