Activation of phasic pontine-wave generator in the rat: a mechanism for expression of plasticity-related genes and proteins in the dorsal hippocampus and amygdala.

A number of behavioral studies have emphasized the importance of interactions between the pontine-wave (P-wave) generator and the dorsal hippocampus (DH) in two-way active avoidance (TWAA) memory processing; however, the direct involvement of the P-wave generator in the TWAA training trial-induced molecular events in the DH and amygdala has not been systematically evaluated. Here we demonstrate that the TWAA learning training trials activate P-wave generator, and increase phosphorylation of CREB (pCREB) and expression of activity-regulated cytoskeletal-associated (Arc) protein, as well as messenger ribonucleic acid (mRNAs) of Arc, brain-derived nerve growth factor (BDNF) and early growth response-1 (Egr-1) in the DH and amygdala. Selective elimination of P-wave-generating cells abolished P-wave activity and suppressed TWAA learning training trial-induced expression of pCREB and Arc proteins and Arc, BDNF and Egr-1 mRNAs in the DH and amygdala.

Vacuolar H+ -ATPase B1 subunit mutations that cause inherited distal renal tubular acidosis affect proton pump assembly and trafficking in inner medullary collecting duct cells.

Point mutations in the B1 subunit of vacuolar H+ -ATPase are associated with impaired ability of the distal nephron to secrete acid (distal renal tubular acidosis). For testing of the hypothesis that these mutations interfere with assembly and trafficking of the H+ -ATPase, constructs that mimic seven known point mutations in inherited distal renal tubular acidosis (M) or wild-type (WT) B1 were transfected into a rat inner medullary collecting duct cell line to express green fluorescence protein (GFP)-B1WT or GFP-B1M fusion proteins. In co-immunoprecipitation studies, GFP-B1WT formed complexes with other H+ -ATPase subunits (c, H, and E), whereas GFP-B1M did not.

Syntaxin 1A has a specific binding site in the H3 domain that is critical for targeting of H+-ATPase to apical membrane of renal epithelial cells.

H(+) transport in the collecting duct is regulated by exocytic insertion of H(+)-ATPase-laden vesicles into the apical membrane. The soluble N-ethylmaleimide-sensitive fusion protein attachment protein (SNAP) receptor (SNARE) proteins are critical for exocytosis. Syntaxin 1A contains three main domains, SNARE N, H3, and carboxy-terminal transmembrane domain.

Munc-18-2 regulates exocytosis of H(+)-ATPase in rat inner medullary collecting duct cells.

Exocytic insertion of H(+)-ATPase into the apical membrane of inner medullary collecting duct (IMCD) cells is dependent on a soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein target receptor (SNARE) complex. In this study we determined the role of Munc-18 in regulation of IMCD cell exocytosis of H(+)-ATPase. We compared the effect of acute cell acidification (the stimulus for IMCD exocytosis) on the interaction of syntaxin 1A with Munc-18-2 and the 31-kDa subunit of H(+)-ATPase.

Syntaxin isoform specificity in the regulation of renal H+-ATPase exocytosis.

Intercalated and inner medullary collecting duct (IMCD) cells of the kidney mediate the transport of H+ by a plasma membrane H+-ATPase. The rate of H+ transport in these cells is regulated by exocytic insertion of H+-ATPase-laden vesicles into the apical membrane. We have shown that the exocytic insertion of proton pumps (H+-ATPase) into the apical membrane of rat IMCD cells, in culture, involves SNARE proteins (syntaxin (synt), SNAP-23, and VAMP).