Fatty acids activate GPR40 and K
+
channels to modulate β-cell function.
Fatty acids activate GPR40 and K
+
channels to modulate β-cell function. Herein, we describe the design and synthesis of
...FAAzo-10
, a light-controllable GPR40 agonist based on Gw-9508.
FAAzo-10
is a potent GPR40 agonist in the
trans
-configuration and can be inactivated on isomerization to
cis
with UV-A light. Irradiation with blue light reverses this effect, allowing
FAAzo-10
activity to be cycled ON and OFF with a high degree of spatiotemporal precision. In dissociated primary mouse β-cells,
FAAzo-10
also inactivates voltage-activated and ATP-sensitive K
+
channels, and allows us to control glucose-stimulated Ca
2+
oscillations in whole islets with light. As such,
FAAzo-10
is a useful tool to study the complex effects, with high specificity, which FA-derivatives such as Gw-9508 exert at multiple targets in mouse β-cells.
The purpose of this study was to describe the dual role of public university administrator and chief executive of a private, institutionally-related foundation and to discover how individuals who ...serve in these roles are impacted by this dual status. The grand tour question was: How do individuals bridge the dual role of public university administrator and chief executive of an institutionally-related foundation? Sub-questions were: What were participants' experiences serving in the dual role? How do individuals describe the dual role? How do they react to challenges of the dual role? What were the benefits and drawbacks of the dual role? Study participants were 15 individuals who served as public university administrators and executives of institutionally-related foundations from institutions with at least $25 million in foundation assets, a student population of at least 5,000 students, at the vice presidential level. Data were collected through personal interviews with each participant. Analysis of the interviews was conducted using open coding. Five propositions emerged from the study: (1) If an institutionally-related foundation lacks the financial and/or organizational maturity to be independent from its host institution, then the dual role is a valuable and appropriate organizational structure. (2) A decision by both the university and the institutionally-related foundation to maintain the dual role is not permanent. If the dual role is to be vital and relevant to their operations, then a periodic review of the role's effectiveness is essential. (3) To be successful in the dual role, one must build a relationship with the university president and the foundation board based on trust and candor. (4) If the institution's president understands not only the dual role, but also the mission, purpose, and responsibilities of the foundation, then the president will be invaluable to the individual serving in the dual role. (5) An up-to-date operating agreement between the university and the foundation is critical to the success of the individual in the dual role.
Purified populations of quiescent human tumour cells were isolated from plateau phase cultures of PMC-22 cells by centrifugal elutriation. Dilution into fresh medium resulted in these quiescent cells ...entering S phase exponentially with a t1/2 of 12 hr, after a 18-20-hr lag period during which cellular RNA content increased. Subsequent studies showed that recruitment of quiescent cells into the cell cycle could be regulated by extracellular pH. When exponentially growing PMC-22 cells were exposed to acidic extracellular pH levels, three growth patterns were observed: 1) Normal growth between pH 7.2 to pH 6.8; 2) A reduction in growth rate associated with accumulation of cells with a G1 DNA content between pH 6.7 and 6.4 (this was also shown to occur in a number of other tumour cell lines); 3) Non-cell-cycle-phase-specific arrest of growth at pH levels less than 6.3. Further studies with purified quiescent cell populations showed the possible existence of a pH-dependent restriction point in the G1 phase of these tumour cells. The implications of these observations to tumour biology are discussed.
Increased levels of the second messenger lipid diacylglycerol (DAG) induce a variety of downstream signaling events including the translocation of C1 domain-containing proteins toward the plasma ...membrane. Here, we introduce three light-sensitive DAGs, termed PhoDAGs, which feature a photoswitchable acyl chain allowing for reversible isomerization under the control of light. The PhoDAGs are inactive in the dark and promote the translocation of proteins that feature C1 domains towards the plasma membrane upon stimulation with UV-A irradiation. This effect is quickly reversed after the termination of photostimulation, or by irradiation with blue light, permitting multiple rounds of translocation and the generation of oscillation patterns. Both novel and conventional isoforms of protein kinase C (PKC), as well as Munc13, can thus be put under optical control. PhoDAGs can be used to control vesicle release in excitable cells, such as mouse pancreatic islets and hippocampal neurons, and modulate synaptic transmission at the neuromuscular junction of
Caenorhabditis elegans
. As such, the PhoDAGs afford an unprecedented degree of spatiotemporal control, particularly with respect to pattern formation, and are broadly applicable tools to unravel various DAG-dependent signaling pathways.
We describe a one-pot strategy for the high yielding, operationally simple synthesis of fluorescent probes for Zn
that bear biological targeting groups and exemplify the utility of our method through ...the preparation of a small library of sensors. Investigation of the fluorescence behaviour of our library revealed that although all behaved as expected in MeCN, under biologically relevant conditions in HEPES buffer, a plasma membrane targeting sensor displayed a dramatic switch on response to excess Zn
as a result of aggregation phenomena. Excitingly,
studies in mouse pancreatic islets demonstrated that this readily available sensor was indeed localised to the exterior of the plasma membrane and clearly responded to the Zn
co-released when the pancreatic beta cells were stimulated to release insulin. Conversely, sensors that target intracellular compartments were unaffected. These results demonstrate that this sensor has the potential to allow the real time study of insulin release from living cells and exemplifies the utility of our simple synthetic approach.
Analogues of N-4-3-(2,4-diamino-1,6-dihydro-6-oxo-5-pyrimidinyl)propylamino benzoyl-L-glutamic acid (5-DACTHF), in which the phenylene group is replaced by either a thienoyl or a thiazolyl group were ...synthesized. These compounds were prepared by reductive amination of suitably protected pyrimidinylpropionaldehyde with the aminoaroyl glutamates. These glutamates were in turn synthesized from the corresponding nitroaroyl carboxylic acids by condensation with protected glutamic acid followed by catalytic reduction. The compounds were tested as inhibitors of methotrexate uptake as a measure of binding to the reduced folate transport system, as inhibitors of glycinamide ribonucleotide transformylase, as substrates for folylpolyglutamate synthetase, and as inhibitors of tumor cell growth in cell culture. The thiophene analogue was found to be equal in activity to 5-DACTHF in the MCF-7 cell growth inhibition assay while the thiazole analogue was 9-fold more active. Indeed this thiazole was over 4 times more active in the MCF-7 cell line than the clinically investigated compound 5,10-dideaza-5,6,7,8-tetrahydrofolic acid (DDATHF).
PDF
