The β‐subunit of the gastric H<sup>+</sup>/K<sup>+</sup>‐ATPase can occur without the α‐subunit

Baldwin, Graham S.

doi:10.1016/0014-5793(90)80473-v

Cited by 8 publications

(2 citation statements)

References 19 publications

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“…It is known that the ␤-subunit is necessary for delivery of the ␣-subunit to the plasma membrane (7,27) and that it has a sequence involved in endocytic retrieval of the pump (5). Furthermore, the ␤-subunit can attain cell surface expression in the absence of the ␣-subunit (27), and a population of ␤-subunit monomers has been identified in the parietal cell (28). Thus, it is conceivable that the ␤-subunit is necessary not only for endocytic retrieval, which is intimately involved in the transition from the stimulated to the resting state (5), but also for recruitment of secretory membranes to the apical membrane of the parietal cell.…”

Section: Discussionmentioning

confidence: 99%

Stomachs of Mice Lacking the Gastric H,K-ATPase α-Subunit Have Achlorhydria, Abnormal Parietal Cells, and Ciliated Metaplasia

Spicer¹,

Miller²,

Andringa³

et al. 2000

Journal of Biological Chemistry

163

135

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The H,K-ATPase of the gastric parietal cell is the most critical component of the ion transport system mediating acid secretion in the stomach. To study the requirement of this enzyme in the development, maintenance, and function of the gastric mucosa, we used gene targeting to prepare mice lacking the ␣-subunit. Homozygous mutant (Atp4a ؊/؊ ) mice appeared healthy and exhibited normal systemic electrolyte and acid-base status but were achlorhydric and hypergastrinemic. Immunocytochemical, histological, and ultrastructural analyses of Atp4a ؊/؊ stomachs revealed the presence of chief cells, demonstrating that the lack of acid secretion does not interfere with their differentiation. Parietal cells were also present in normal numbers, and despite the absence of ␣-subunit mRNA and protein, the ␤-subunit was expressed. However, Atp4a ؊/؊ parietal cells had dilated canaliculi and lacked typical canalicular microvilli and tubulovesicles, and subsets of these cells contained abnormal mitochondria and/or massive glycogen stores. Stomachs of adult Atp4a؊/؊ mice exhibited metaplasia, which included the presence of ciliated cells. We conclude that ablation of the H,K-ATPase ␣-subunit causes achlorhydria and hypergastrinemia, severe perturbations in the secretory membranes of the parietal cell, and metaplasia of the gastric mucosa; however, the absence of the pump appears not to perturb parietal cell viability or chief cell differentiation.

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Section: Discussionmentioning

confidence: 99%

Stomachs of Mice Lacking the Gastric H,K-ATPase α-Subunit Have Achlorhydria, Abnormal Parietal Cells, and Ciliated Metaplasia

Spicer¹,

Miller²,

Andringa³

et al. 2000

Journal of Biological Chemistry

163

135

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“…The intracellular pathways of CCK and gastrins action in kidney cells are not known but might be dependent on either a specific channel-mediated Ca 2þ influx or the intracellular release of Ca 2þ mediated by inositol lipid metabolism [2]. The stimulatory effect of gastrin on Na þ -H þ exchange via CCK B R in the pancreatic acinar cell might be similar to the regulation of the activity of the Na þ ,H þ -ATPase in the kidney [51][52][53][54][55][56]. It might, however, not be valid to draw parallels between effects on exocrine tissue and the kidney, therefore further studies on the effects of gastrin and CCK on electrolyte transport and second-messenger systems in the kidney are needed.…”

Section: Discussionmentioning

confidence: 99%

Gastrin/cholecystokinin type B receptors in the kidney: molecular, pharmacological, functional characterization, and localization

Weerth

Jonás

Schade

et al. 1998

Eur J Clin Investigation

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Background Gastrin/cholecystokinin type B receptors (CCKBRs) can be found on parietal cells and smooth muscle cells and are the predominant brain CCK receptors. Recent cloning studies indicate that this receptor type might also be expressed in the kidney. Materials and methods We used Northern blot analysis in guinea pig. kidney and reverse transcriptase polymerase chain reaction (RT‐PCR) in several murine kidney cell lines to evaluate this organ for the expression of the CCKBRs. The receptor was pharmacologically characterized by displacement experiments using [125I]‐BH‐CCKs and various agonists and antagonists. Polyclonal antibodies vs. the CCKBRs were raised in chicken, and immunohistochemistry on tissue sections was used to localize the receptor within the organ. The effect of gastrin on renal cell growth was measured using proximal tubulus (MCT) cells, which were cultured with gastrin (10−9 M) for 24–72 h. Cell counts and [3H]‐thymidine incorporation experiments were performed. Results CCKBR transcripts can be detected in kidney RNA (tubules > glomeruli > interstitium). RT‐PCR revealed CCKBR transcripts in proximal tubules (MCT cells) and in mesangium (MMC). The medullary thick ascending limb of Henle's loop and several control tissues such as liver and muscle were negative. Displacement experiments using [125I]‐BH‐CCK and various agonists and antagonists identified binding sites with typical CCKBR pharmacology. CCKBRs were localized in the proximal tubulus, distal collecting ducts and mesangium cells. Treatment of rested MCT cells with gastrin 17‐1 induced cell proliferation and [3H]‐thymidine incorporation by at least 40% compared with normal growth (P < 0.05). Conclusion These results show for the first time that CCKBRs are present in selected areas of the kidney, and strongly confirm our previous observation that this organ expresses binding sites for [125I]‐gastrin. Furthermore, gastrin might act as a growth factor in the kidney.

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Calponin and the composition of smooth muscle thin filaments

Lehman

1991

J Muscle Res Cell Motil

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The β‐subunit of the gastric H⁺/K⁺‐ATPase can occur without the α‐subunit

Cited by 8 publications

References 19 publications

Stomachs of Mice Lacking the Gastric H,K-ATPase α-Subunit Have Achlorhydria, Abnormal Parietal Cells, and Ciliated Metaplasia

Stomachs of Mice Lacking the Gastric H,K-ATPase α-Subunit Have Achlorhydria, Abnormal Parietal Cells, and Ciliated Metaplasia

Gastrin/cholecystokinin type B receptors in the kidney: molecular, pharmacological, functional characterization, and localization

Calponin and the composition of smooth muscle thin filaments

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The β‐subunit of the gastric H+/K+‐ATPase can occur without the α‐subunit

Cited by 8 publications

References 19 publications

Stomachs of Mice Lacking the Gastric H,K-ATPase α-Subunit Have Achlorhydria, Abnormal Parietal Cells, and Ciliated Metaplasia

Stomachs of Mice Lacking the Gastric H,K-ATPase α-Subunit Have Achlorhydria, Abnormal Parietal Cells, and Ciliated Metaplasia

Gastrin/cholecystokinin type B receptors in the kidney: molecular, pharmacological, functional characterization, and localization

Calponin and the composition of smooth muscle thin filaments

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The β‐subunit of the gastric H⁺/K⁺‐ATPase can occur without the α‐subunit