Calcineurin-dependent nuclear import of the transcription factor Crz1p requires Nmd5p

Calcineurin is a conserved Ca2+/calmodulin-specific serine-threonine protein phosphatase that mediates many Ca2+-dependent signaling events. In yeast, calcineurin dephosphorylates Crz1p, a transcription factor that binds to the calcineurin-dependent response element, a 24-bp promoter element. Calcineurin-dependent dephosphorylation of Crz1p alters Crz1p nuclear localization. This study examines the mechanism by which calcineurin regulates the nuclear localization of Crz1p in more detail. We describe the identification and characterization of a novel nuclear localization sequence (NLS) in Crz1p, which requires both basic and hydrophobic residues for activity, and show that the karyopherin Nmd5p is required for Crz1p nuclear import. We also demonstrate that the binding of Crz1p to Nmd5p is dependent upon its phosphorylation state, indicating that nuclear import of Crz1p is regulated by calcineurin. Finally, we demonstrate that residues in both the NH2- and COOH-terminal portions of Crz1p are required for regulated Crz1p binding to Nmd5p, supporting a model of NLS masking for regulating Crz1p nuclear import

Test-Retest Reliability of Postural Control Assessment on Biodex BioSway™

Background. Recent protocols for posturographic assessment of postural control and balance have included head shake test conditions to challenge the vestibular contributions of postural control in an effort to increase the diagnostic accuracy of identifying individuals with impaired balance. However, evidence is limited regarding the test-retest reliability of such assessment protocols. Purpose. The purpose of this study was twofold: to determine the test-retest reliability of postural control assessment on the Biodex Biosway™, an accessible and field expedient tool for posturographic assessment, and to determine the test-retest reliability of the Head Shake Sensory Interaction and Balance Test (HS-SIB), an adaptation of the modified Clinical Test of Sensory Interaction and Balance (mCTSIB) which adds two head shake conditions to challenge the vestibular contributions to postural control. Study Design. This was a correlational time series cohort study completed in a biomechanics laboratory. Methods. The sample consisted of nineteen healthy adults (10 females, 9 males). Sway Index, Equilibrium Score, and the area of the ellipse enclosing 95% of the anterior-posterior (AP) and medial-lateral (ML) center of gravity (COG) displacement (AREA95) are the 3 summary variables. Standard Error of Measurement (SEM) and Minimum Detectable Change (MDC) are also reported. Results. Test-retest reliability was generally poor with limited exceptions. Moderate to good reliability was observed for the more challenging stance conditions (ICC range 0.58-0.81), including those with head shake. Conclusions. Field-expedient systems, such as the Biodex BioSway™, may offer reliable posturographic testing where gold-standard methods are not available. Clinicians should be aware that less demanding test conditions have limited reliability; however, test-retest reliability of this assessment tool is improved with more challenged stance conditions and the inclusion of a head shake task

Role of Phospholipase A2 in Retrograde Transport of Ricin

Ricin is a protein toxin classified as a bioterror agent, for which there are no known treatment options available after intoxication. It is composed of an enzymatically active A-chain connected by a disulfide bond to a cell binding B-chain. After internalization by endocytosis, ricin is transported retrogradely to the Golgi and ER, from where the ricin A-chain is translocated to the cytosol where it inhibits protein synthesis and thus induces cell death. We have identified cytoplasmic phospholipase A2 (PLA2) as an important factor in ricin retrograde transport. Inhibition of PLA2 protects against ricin challenge, however the toxin can still be endocytosed and transported to the Golgi. Interestingly, ricin transport from the Golgi to the ER is strongly impaired in response to PLA2 inhibition. Confocal microscopy analysis shows that ricin is still colocalized with the trans-Golgi marker TGN46 in the presence of PLA2 inhibitor, but less is colocalized with the cis-Golgi marker GM130. We propose that PLA2 inhibition results in impaired ricin transport through the Golgi stack, thus preventing it from reaching the ER. Consequently, ricin cannot be translocated to the cytosol to exert its toxic action

Regulation of the Na+/K+-ATPase Ena1 Expression by Calcineurin/Crz1 under High pH Stress: A Quantitative Study

[EN] Regulated expression of the Ena1 Na+-ATPase is a crucial event for adaptation to high salt and/or alkaline pH stress in the budding yeast Saccharomyces cerevisiae. ENA1 expression is under the control of diverse signaling pathways, including that mediated by the calcium-regulatable protein phosphatase calcineurin and its downstream transcription factor Crz1. We present here a quantitative study of the expression of Ena1 in response to alkalinization of the environment and we analyze the contribution of Crz1 to this response. Experimental data and mathematical models substantiate the existence of two stress-responsive Crz1-binding sites in the ENA1 promoter and estimate that the contribution of Crz1 to the early response of the ENA1 promoter is about 60%. The models suggest the existence of a second input with similar kinetics, which would be likely mediated by high pH-induced activation of the Snf1 kinase.This work was supported by grants BFU2011-30197-C3-01, BFU2014-54591-C2-1-P and EUI2009-04147 (SysMo2) to JA. (Ministry of Industry and Competitivity, Spain, and Fondo Europeo de Desarrollo Regional [FEDER]). JA is the recipient of an Ajut 2014SGR-4 award (Generalitat de Catalunya). DC was recipient of a predoctoral fellowship from the Spanish Ministry of Education. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Petrezsélyová, S.; López-Malo, M.; Canadell, D.; Roque, A.; Serra-Cardona, A.; Marques Romero, MC.; Vilaprinyó, E.... (2016). Regulation of the Na+/K+-ATPase Ena1 Expression by Calcineurin/Crz1 under High pH Stress: A Quantitative Study. PLoS ONE. 11(6):e0158424-e0158424. https://doi.org/10.1371/journal.pone.0158424Se0158424e015842411

The phospholipase complex PAFAH Ib regulates the functional organization of the Golgi complex

We report that platelet-activating factor acetylhydrolase (PAFAH) Ib, comprised of two phospholipase A(2) (PLA(2)) subunits, α1 and α2, and a third subunit, the dynein regulator lissencephaly 1 (LIS1), mediates the structure and function of the Golgi complex. Both α1 and α2 partially localize on Golgi membranes, and purified catalytically active, but not inactive α1 and α2 induce Golgi membrane tubule formation in a reconstitution system. Overexpression of wild-type or mutant α1 or α2 revealed that both PLA(2) activity and LIS1 are important for maintaining Golgi structure. Knockdown of PAFAH Ib subunits fragments the Golgi complex, inhibits tubule-mediated reassembly of intact Golgi ribbons, and slows secretion of cargo. Our results demonstrate a cooperative interplay between the PLA(2) activity of α1 and α2 with LIS1 to facilitate the functional organization of the Golgi complex, thereby suggesting a model that links phospholipid remodeling and membrane tubulation to dynein-dependent transport

INFLUENCE OF NITROGEN FORM AND OTHER NUTRITIONAL FACTORS ON PLANT GROWTH AND ION ACCUMULATION IN SOLUTION CULTURE.

Abstract not availabl

Etiology of the developing eye in myelencephalic blebs (my) mice

The etiology of the eye defects in myelencephalic blebs (my) mutant mice has been poorly understood for almost seventy years. Embryos from 9 to 14 M days of gestation were subjected to Alcian blue 8GX staining for acidic glycosaminoglycan deposition in basement membrane structures of the developing eye in my stock and control specimens. In addition 12 day embryos were subjected to avidinbiotin- peroxidase labelling for laminin. At 9 - 9 M days of gestation more Alcian blue positive extracellular matrix was found in the region between the optic vesicle and the overlying putative lens ectoderm in the my stock embryos. By 12 days, there was an irregular and lesser amount of deposition of glycosaminoglycans in the len's capsule and in the «inner lirniting membrane~ of the presumptive neural retina; however, the deposition of laminin appeared to be greater in the inner lirniting membrane of the my eye. By 14 days, the damage to the eye in the my embryos can be quite extensive, and the deposition of glycosaminoglycans was very meager in this situation. It appears that irregular deposition of glycosaminoglycans in the extracellular matrix and possible increase in the amount of laminin in basement structures in my embryos indicate disruption of the normal histochemistry involved in the development of the eye. Altered histochemistry may in turn indicate changes in permeability between cells of the developing tissues which result in the blebbing