Metabolon disruption: a mechanism that regulates bicarbonate transport

Carbonic anhydrases (CA) catalyze the reversible conversion of CO(2) to HCO(3)(−). Some bicarbonate transporters bind CA, forming a complex called a transport metabolon, to maximize the coupled catalytic/transport flux. SLC26A6, a plasma membrane Cl(−)/HCO(3)(−) exchanger with a suggested role in pancreatic HCO(3)(−) secretion, was found to bind the cytoplasmic enzyme CAII. Mutation of the identified CAII binding (CAB) site greatly reduced SLC26A6 activity, demonstrating the importance of the interaction. Regulation of SLC26A6 bicarbonate transport by protein kinase C (PKC) was investigated. Angiotensin II (AngII), which activates PKC, decreased Cl(−)/HCO(3)(−) exchange in cells coexpressing SLC26A6 and AT(1a)-AngII receptor. Activation of PKC reduced SLC26A6/CAII association in immunoprecipitates. Similarly, PKC activation displaced CAII from the plasma membrane, as monitored by immunofluorescence. Finally, mutation of a PKC site adjacent to the SLC26A6 CAB site rendered the transporter unresponsive to PKC. PKC therefore reduces CAII/SLC26A6 interaction, reducing bicarbonate transport rate. Taken together, our data support a mechanism for acute regulation of membrane transport: metabolon disruption

Therapeutic lighting design for the elderly: a review

This article is closed access, it will be published in the journal, Perspectives in Public Health [Sage Publications © Royal Society for Public Health]. The definitive version is available at: http://dx.doi.org/10.1177/1757913911422288Aims: Research suggests that specialised lighting design is essential to cater for the elderly users of a building because of reduced visual performance with increased age. This review aims to document what is known of the physical and psychological aspects of lighting and their role in promoting a healthy and safe environment for the elderly. Methods: A methodical review was carried out of published literature on the physical and psychological impacts of light on the elderly. Design standards and guides from professional organizations were evaluated to identify synergies and gaps between the evidence base and current practice. Results: Lighting has been identified as a significant environmental attribute responsible for promoting physical and mental health of the elderly. The evidence related to visual performance was found to be robust. However, guides and standards appeared to have focused mostly on illumination requirements for specific tasks and have lacked detailed guidelines on vertical lighting and luminance design. This review has identified a growing body of evidence on the therapeutic benefits of lighting and its use in treating psychological disorders among the elderly. The experiments using light as a therapy have improved our understanding of the underlying principles, but the integration of therapeutic aspects of lighting in design practice and guidelines is lacking. Conclusions: While design guidelines discuss the physical needs of lighting for the elderly fairly well, they lack incorporation of photobiological impacts. Despite positive outcomes from research, the implementation of therapeutic aspects of lighting in buildings is still debatable due to insufficient relevant investigations and robustness of their findings. Collaborations between designers and physicians can contribute in delivering customised lighting solutions by considering disease types and needs. Further investigation needs to be carried out for translating therapeutic benefits to photometric units to implement them in building lighting design