SUNDAY, DECEMBER 4- Late Abstracts 1 - Molecular Biology of the ...

SUNDAY
cGKII was increased in SHR ileum and colon as compared to WKY controls. Captopril treatment
of SHR caused a partial reversal of these changes, and a significant reversal of NHERF-1.
These changes do not seem to be due to any difference in the microsomal protein yield. We
demonstrate evidence of mild inflammation in SHR colon and ileum due to hypertension. Our
findings showed decreased expression of NHE-1, -3 and NHERF-1, which together would
suppress uptake of water and NaCl from the GI-tract and hence may be a counteracting
response in the development of hypertension in this model.
Acknowledgments: Kuwait University Research administration (grant YM 06/2010) and College
of Graduate Studies for financial support and Shared Core Facility, Health Science Center,
Kuwait University for allowing to use the instrumentation.
2010
Gustatory receptors not G protein coupled receptors are required for the response to Lcanavanine.
Y. Lee 1 , M. Kang 2 , J. Shim 3 , C. Cheong 2 , S. Moon 2 , C. Montell 1 ; 1 Department of Biological
Chemistry and Neuroscience, Center for Sensory Biology, The Johns Hopkins University School
of Medicine, 2 Department of Oral Biology, Brain Korea21 project, Yonsei University College of
Dentistry, Seoul, Korea, 3 Department of Phamacology, Yonsei University College of Medicine,
Seoul, Korea
Insects respond to their surroundings through sensing chemical cues and then decide their
behaviors. Gustatory sense is one of the most important chemical sensory systems. There are
68 gustatory receptors (GRs) encoded by 60 gustatory receptor genes. Several gustatory
receptors are known to be required for sensing of sugars or bitter chemicals, such as caffeine.
However, the functions of most GRs are unknown. Here we show that Gr8a and Gr66a are
required for sensing insecticide, L-canavainine, which is produced by plants. Gr8a is expressed
in a subset of Gr66a expressing gustatory receptor neurons (GRNs). The action potentials to Lcanavanine
are detected only in the Gr8a expressing neuron. The consistence of Gr8a
expression pattern and electrophysiological response to L-canavanine suggests the possibility
that Gr8a is the specific receptor to L-canavanine, while Gr66a is the broad receptor to bitter
chemicals. In contrast, DmXR, one of the G-protein coupled receptors (GPCRs), has been
reported to be required for detecting L-canavanine. However, DmXR missing flies show the
avoidance to L-canavanine and action potentials to L-canavanine as wild type flies do in our
results. These results imply that Gr8a and Gr66a are indispensible for detection of Lcanavanine,
but not DmXR.
2011
NHERF- 1 Modulates Intestinal NaPi transporter NaPi-2b expression in Apical Microvilli.
H. Giral 1 , Y. Caldas 1 , L. Lanzano 2 , E. Gratton 2 , M. Levi 1 ; 1 University of Colorado Denver, Aurora,
CO, 2 University of California Irvine, CA
The regulation of phosphate (Pi) homeostasis is maintained by the coordinated function of the renal and
intestinal phosphate transporters. Several PDZ (PSD-95/discs large/ZO-1 homologous) domain
proteins, including NHERF-1, PDZK1, ShanK2, and PIST play an important role in the regulation of the
renal sodium-phosphate (NaPi) co-transporters (NaPi-2a and NaPi-2c). The main mediator of intestinal
sodium dependent transcellular Pi transport, NaPi-2b, also contains a PDZ-binding motif consensus in
the C-terminal region. However, interactions of the transporter NaPi-2b with PDZ proteins have been
not described and their potential role in regulation of the intestinal transporter is not known. For this
purpose we performed studies with knock-out (KO) mice models and cell culture to determine a
potential role for NHERF-1 and PDZK1 in the regulation of NaPi-2b.