A dynamic cpSRP43-Albino3 interaction mediates translocase regulation of chloroplast signal recognition particle (cpSRP)-targeting components.

The chloroplast signal recognition particle (cpSRP) and its receptor, chloroplast FtsY (cpFtsY), form an essential complex with the translocase Albino3 (Alb3) during post-translational targeting of light-harvesting chlorophyll-binding proteins (LHCPs). Here, we describe a combination of studies that explore the binding interface and functional role of a previously identified cpSRP43-Alb3 interaction. Using recombinant proteins corresponding to the C terminus of Alb3 (Alb3-Cterm) and various domains of cpSRP43, we identify the ankyrin repeat region of cpSRP43 as the domain primarily responsible for the interaction with Alb3-Cterm. Furthermore, we show Alb3-Cterm dissociates a cpSRP·LHCP targeting complex in vitro and stimulates GTP hydrolysis by cpSRP54 and cpFtsY in a strictly cpSRP43-dependent manner. These results support a model in which interactions between the ankyrin region of cpSRP43 and the C terminus of Alb3 promote distinct membrane-localized events, including LHCP release from cpSRP and release of targeting components from Alb3.

Improving the Efficiency and Ease of Healthcare Analysis Through Use of Data Visualization Dashboards.

The digitization of a patient's health record has profoundly impacted medicine and healthcare. The compilation and accessibility of medical history has provided clinicians an unprecedented, holistic account of a patient's conditions, procedures, medications, family history, and social situation. In addition to the bedside benefits, this level of information has opened the door for population-level monitoring and research, the results of which can be used to guide initiatives that are aimed at improving quality of care. Cerner Corporation partners with health systems to help guide population management and quality improvement projects. With such an enormous and diverse client base-varying in geography, size, organizational structure, and analytic needs-discerning meaning in the data and how they fit with that particular hospital's goals is a slow, difficult task that requires clinical, statistical, and technical literacy. This article describes the development of dashboards for efficient data visualization at the healthcare facility level. Focusing on two areas with broad clinical importance, sepsis patient outcomes and 30-day hospital readmissions, dashboards were developed with the goal of aggregating data and providing meaningful summary statistics, highlighting critical performance metrics, and providing easily digestible visuals that can be understood by a wide range of personnel with varying levels of skill and areas of expertise. These internal-use dashboards have allowed associates in multiple roles to perform a quick and thorough assessment on a hospital of interest by providing the data to answer necessary questions and to identify important trends or opportunities. This automation of a previously manual process has greatly increased efficiency, saving hours of work time per hospital analyzed. Additionally, the dashboards have standardized the analysis process, ensuring use of the same metrics and processes so that overall themes can be compared across hospitals and health systems.

The membrane-binding motif of the chloroplast signal recognition particle receptor (cpFtsY) regulates GTPase activity.

The chloroplast signal recognition particle (cpSRP) and its receptor (cpFtsY) function in thylakoid biogenesis to target integral membrane proteins to thylakoids. Unlike cytosolic SRP receptors in eukaryotes, cpFtsY partitions between thylakoid membranes and the soluble stroma. Based on sequence alignments, a membrane-binding motif identified in Escherichia coli FtsY appears to be conserved in cpFtsY, yet whether the proposed motif is responsible for the membrane-binding function of cpFtsY has yet to be shown experimentally. Our studies show that a small N-terminal region in cpFtsY stabilizes a membrane interaction critical to cpFtsY function in cpSRP-dependent protein targeting. This membrane-binding motif is both necessary and sufficient to direct cpFtsY and fused passenger proteins to thylakoids. Our results demonstrate that the cpFtsY membrane-binding motif may be functionally replaced by the corresponding region from E. coli, confirming that the membrane-binding motif is conserved among organellar and prokaryotic homologs. Furthermore, the capacity of cpFtsY for lipid binding correlates with liposome-induced GTP hydrolysis stimulation. Mutations that debilitate the membrane-binding motif in cpFtsY result in higher rates of GTP hydrolysis, suggesting that negative regulation is provided by the intact membrane-binding region in the absence of a bilayer. Furthermore, NMR and CD structural studies of the N-terminal region and the analogous region in the E. coli SRP receptor revealed a conformational change in secondary structure that takes place upon lipid binding. These studies suggest that the cpFtsY membrane-binding motif plays a critical role in the intramolecular communication that regulates cpSRP receptor functions at the membrane.