NHERF3 (PDZK1) Contributes to Basal and Calcium Inhibition of NHE3 Activity in Caco-2BBe Cells

Zachos, Nicholas C.; Li, Xuhang; Kovbasnjuk, Olga; Hogema, Boris M.; Sarker, Rafiquel; Lee, Luke J.; Li, Min; Jonge, Hugo R. de; Donowitz, Mark

doi:10.1074/jbc.m109.012641

Cited by 34 publications

(52 citation statements)

References 51 publications

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“…Consistent with previous reports, Fig. 8A shows that SB-216763 increases the phosphorylation of GSK-3␤ on Ser 9 , suggesting decreased GSK-3␤ activity. Exposure to a GSK-3 inhibitor significantly reduced basal NHE3 activity (GSK-3i (10 M) for 60 min (p Ͻ 0.05) (Fig.…”

Section: Volume 289 • Number 9 • February 28 2014supporting

confidence: 81%

AKT and GSK-3 Are Necessary for Direct Ezrin Binding to NHE3 as Part of a C-terminal Stimulatory Complex

Singh

Lin

Yang

et al. 2014

Journal of Biological Chemistry

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Background: Phosphoinositides and ezrin form a complex with NHE3, which stimulates basal transport activity. How this complex is regulated is unknown. Results: GSK-3 and Akt stimulate NHE3 activity by changing ezrin binding. Conclusion: Sequential effects of two kinase regulate the association of NHE3 with ezrin to affect basal activity. Significance: A novel Ser cluster in the NHE3 C-terminal domain regulates its ezrin binding.

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Section: Volume 289 • Number 9 • February 28 2014supporting

confidence: 81%

AKT and GSK-3 Are Necessary for Direct Ezrin Binding to NHE3 as Part of a C-terminal Stimulatory Complex

Singh

Lin

Yang

et al. 2014

Journal of Biological Chemistry

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“…PDZK1 anchors (or facilitates retention of) NHE3 and a number of other transporters in the brush border membrane (1,6,19,34,46,51). DRA and NHE3 as well as PDZK1 are associated with lipid rafts.…”

Section: Discussionmentioning

confidence: 99%

Activity and PI3-kinase dependent trafficking of the intestinal anion exchanger downregulated in adenoma depend on its PDZ interaction and on lipid rafts

Lissner

Nold

Hsieh

et al. 2010

American Journal of Physiology-Gastrointestinal and Liver Physi

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The Cl/HCO3 exchanger downregulated in adenoma (DRA) mediates electroneutral NaCl absorption in the intestine together with the apical Na/H exchanger NHE3. Lipid rafts (LR) modulate transport activity and are involved in phosphatidylinositol 3-kinase (PI3-kinase)-dependent trafficking of NHE3. Although DRA and NHE3 interact via PDZ adaptor proteins of the NHERF family, the role of LR and PDZ proteins in the regulation of DRA is unknown. We examined the association of DRA with LR using the nonionic detergent Triton X-100. DRA cofractionated with LR independently of its PDZ binding motif. Furthermore, DRA interacts with PDZK1, E3KARP, and IKEPP in LR, although their localization within lipid rafts is independent of DRA. Disruption of LR integrity resulted in the disappearance of DRA from LR, in a decrease of its surface expression and in a reduction of its activity. In HEK cells the inhibition of DRA by LR disruption was entirely dependent on the presence of the PDZ interaction motif. In addition, in Caco-2/BBE cells the inhibition by LR disruption was more pronounced in wild-type DRA than in mutated DRA (DRA-ETKFminus; lacking the PDZ binding motif)-expressing cells. Inhibition of PI3-kinase decreased the activity and the cell surface expression of wild-type DRA but not of DRA-ETKFminus; the partitioning into LR was unaffected. Furthermore, simultaneous inhibition of PI3-kinase and disruption of LR did not further decrease DRA activity and cell surface expression compared with LR disruption only. These results suggest that the activity of DRA depends on its LR association, on its PDZ interaction, and on PI3-kinase activity.

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“…The same process can be observed when Caco-2 cells are stimulated with CCh that gives increased intracellular Ca 2ϩ , leading to dissociation of NHE3 from PDZK1 and the subsequent internalization of NHE3. The molecular mechanisms behind this finding is still unclear, but the Ca 2ϩ -dependent uncoupling of PDZK1 from NHE3 occurs in vivo but not in vitro, as purified recombinant NHE3 and PDZK1 proteins interact independent of Ca 2ϩ (50). Thus Ca 2ϩ -dependent dissociation of NHE3 from PDZK1 requires additional proteins, most likely additional adapter and effector protein such as PDZ proteins and kinases, existing in vivo.…”

Section: Discussionmentioning

confidence: 99%

Carbachol-induced MUC17 endocytosis is concomitant with NHE3 internalization and CFTR membrane recruitment in enterocytes

Pelaseyed

Gustafsson

et al. 2013

American Journal of Physiology-Cell Physiology

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We have reported that transmembrane mucin MUC17 binds PDZ protein PDZK1, which retains MUC17 apically in enterocytes. MUC17 and transmembrane mucins MUC3 and MUC12 are suggested to build the enterocyte apical glycocalyx. Carbachol (CCh) stimulation of the small intestine results in gel-forming mucin secretion from goblet cells, something that requires adjacent enterocytes to secrete chloride and bicarbonate for proper mucin formation. Surface labeling and confocal imaging demonstrated that apically expressed MUC17 in Caco-2 cells and Muc3(17) in murine enterocytes were endocytosed upon stimulation with CCh. Relocation of MUC17 in response to CCh was specific as MUC3 and MUC12 did not relocate following CCh stimulation. MUC17 colocalized with PDZK1 under basal conditions, while MUC17 relocated to the terminal web and into early endosomes after CCh stimulation. CCh stimulation concomitantly internalized the Na ϩ/ H ϩ exchanger 3 (NHE3) and recruited cystic fibrosis transmembrane conductance regulator (CFTR) to the apical membranes, a process that was important for CFTR-mediated bicarbonate secretion necessary for proper gel-forming mucin unfolding. The reason for the specific internalization of MUC17 is not understood, but it could limit the diffusion barrier for ion secretion caused by the apical enterocyte glycocalyx or alternatively act to sample luminal bacteria. Our results reveal well-orchestrated mucus secretion and trafficking of ion channels and the MUC17 mucin. MUC17; Muc3(17), PDZK1; NHE3; CFTR MUCINS ARE LARGE O-GLYCOSYLATED proteins and the major components of the mucus that covers surfaces of luminal organs such as the lungs as well as the gastrointestinal and urogenital tracts. There are four human gel-forming mucins (MUC2, MUC5AC, MUC5B, and MUC6) that form large polymeric complexes with gel-like properties when secreted from goblet cells or glands (20). A second group of mucins is the transmembrane mucins that either belong to the NIDO (nidogen)-AMOP (adhesion associated domain in MUC4 and other proteins)-vWD (von Willebrand factor type D) family (MUC4) or the SEA (sea urchin sperm protein, enterokinase, and agrin) family (MUC1, MUC3, MUC12, MUC13, MUC16, and MUC17), as determined by the juxtamembrane extracellular functional domain(s) (24).MUC17, and its murine orthologue Muc3(17), are the main transmembrane mucins expressed in the human and mouse small intestines (12,32). MUC17 has a domain structure typical for most transmembrane mucins (Fig. 1A). An NH 2 -terminal signal sequence is followed by a repeated PTS (proline-, serine-, and threonine-rich) sequence, rich in proline, threonine, and serine amino acid residues. The serine and threonine residues carry O-glycans, which are added during posttranslational processing of the mucin in the Golgi apparatus to generate an extended bottle-brush-shaped mucin domain (2, 10). A SEA domain is located between the mucin domain and transmembrane domain. This conserved domain is cleaved in an autocatalytically strain-dependent manner in the endoplasmic ret...

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NHERF3 (PDZK1) Contributes to Basal and Calcium Inhibition of NHE3 Activity in Caco-2BBe Cells

Cited by 34 publications

References 51 publications

AKT and GSK-3 Are Necessary for Direct Ezrin Binding to NHE3 as Part of a C-terminal Stimulatory Complex

AKT and GSK-3 Are Necessary for Direct Ezrin Binding to NHE3 as Part of a C-terminal Stimulatory Complex

Activity and PI3-kinase dependent trafficking of the intestinal anion exchanger downregulated in adenoma depend on its PDZ interaction and on lipid rafts

Carbachol-induced MUC17 endocytosis is concomitant with NHE3 internalization and CFTR membrane recruitment in enterocytes

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