scholarly journals The 46 kDa mannose-6-phosphate receptor contains a signal for basolateral sorting within the 19 juxtamembrane cytosolic residues

1997 ◽  
Vol 327 (3) ◽  
pp. 811-818 ◽  
Author(s):  
Roberto BRESCIANI ◽  
Kristin DENZER ◽  
Regina POHLMANN ◽  
Kurt VON FIGURA
Keyword(s):  
Kidney Cells ◽  
Madin Darby Canine Kidney ◽  
Reporter Protein ◽  
Sorting Signals ◽  
Critical Residues ◽  
Mannose 6 Phosphate ◽  
The One ◽  
Mpr 46 ◽  
Darby Canine Kidney ◽  
Canine Kidney

The cytosolic domain of the 46 kDa mannose-6-phosphate receptor (MPR 46) contains a signal that mediates sorting of the receptor and of a reporter protein to the basolateral surface domain of Madin-Darby canine kidney cells. Progressive truncation of the 67 cytosolic residues indicated that the 19 juxtamembrane residues are sufficient for basolateral sorting. Alanine/glycine-scanning mutagenesis identified Glu-11 and Ala-17 as the critical residues between residues 7 and 19. Glu-11 is also of critical importance for the one of the three internalization signals in the cytosolic tail of the receptor [Denzer, Weber, Hille-Rehfeld, von Figura and Pohlmann (1997) Biochem. J. 326, 497-505]. Although overlapping, the signals for basolateral sorting and internalization depend on different residues. The basolateral sorting signal of MPR 46 is distinct from tyrosine- or dileucine-based basolateral sorting signals and also lacks similarity to the few other basolateral signals that do not fall into these two classes.

scholarly journals SpecificN-Glycans Direct Apical Delivery of Transmembrane, but Not Soluble or Glycosylphosphatidylinositol-anchored Forms of Endolyn in Madin-Darby Canine Kidney Cells

2004 ◽  
Vol 15 (3) ◽  
pp. 1407-1416 ◽  
Author(s):  
Beth A. Potter ◽  
Gudrun Ihrke ◽  
Jennifer R. Bruns ◽  
Kelly M. Weixel ◽  
Ora A. Weisz
Keyword(s):  
Transmembrane Protein ◽  
Site Directed Mutagenesis ◽  
Kidney Cells ◽  
Apical Surface ◽  
Glycosidase Inhibitors ◽  
Madin Darby Canine Kidney ◽  
Reporter Protein ◽  
Apical Sorting ◽  
Darby Canine Kidney ◽  
Canine Kidney

The sialomucin endolyn is a transmembrane protein with a unique trafficking pattern in polarized Madin-Darby canine kidney cells. Despite the presence of a cytoplasmic tyrosine motif that, in isolation, is sufficient to mediate basolateral sorting of a reporter protein, endolyn predominantly traverses the apical surface en route to lysosomes. Apical delivery of endolyn is disrupted in tunicamycin-treated cells, implicating a role for N-glycosylation in apical sorting. Site-directed mutagenesis of endolyn's eight N-glycosylation sites was used to identify two N-glycans that seem to be the major determinants for efficient apical sorting of the protein. In addition, apical delivery of endolyn was disrupted when terminal processing of N-glycans was blocked using glycosidase inhibitors. Missorting of endolyn occurred independently of the presence or absence of the basolateral sorting signal, because apical delivery was also inhibited by tunicamycin when the cytoplasmic tyrosine motif was mutated. However, we found that apical secretion of a soluble mutant of endolyn was N-glycan independent, as was delivery of glycosylphosphatidylinositol-anchored endolyn. Thus, specific N-glycans are only essential for the apical sorting of transmembrane endolyn, suggesting fundamental differences in the mechanisms by which soluble, glycosylphosphatidylinositol-anchored, and transmembrane proteins are sorted.

scholarly journals Inhibition by brefeldin A of protein secretion from the apical cell surface of Madin-Darby canine kidney cells.

1991 ◽  
Vol 266 (27) ◽  
pp. 17729-17732 ◽  
Author(s):  
S.H. Low ◽  
S.H. Wong ◽  
B.L. Tang ◽  
P. Tan ◽  
V.N. Subramaniam ◽  
...  
Keyword(s):  
Cell Surface ◽  
Protein Secretion ◽  
Apical Cell ◽  
Brefeldin A ◽  
Kidney Cells ◽  
Madin Darby Canine Kidney ◽  
Darby Canine Kidney ◽  
Canine Kidney

MST3 is involved in ENaC-mediated hypertension

2019 ◽  
Vol 317 (1) ◽  
pp. F30-F42
Author(s):  
Te-Jung Lu ◽  
Wei-Chih Kan ◽  
Sung-Sen Yang ◽  
Si-Tse Jiang ◽  
Sheng-Nan Wu ◽  
...  
Keyword(s):  
Kidney Cells ◽  
Hypertensive Rats ◽  
Madin Darby Canine Kidney ◽  
Spontaneously Hypertensive ◽  
Hypomorphic Mutation ◽  
And Oxidative Stress ◽  
Darby Canine Kidney ◽  
Canine Kidney

Liddle syndrome is an inherited form of human hypertension caused by increasing epithelial Na+ channel (ENaC) expression. Increased Na+ retention through ENaC with subsequent volume expansion causes hypertension. In addition to ENaC, the Na+-K+-Cl− cotransporter (NKCC) and Na+-Cl− symporter (NCC) are responsible for Na+ reabsorption in the kidneys. Several Na+ transporters are evolutionarily regulated by the Ste20 kinase family. Ste20-related proline/alanine-rich kinase and oxidative stress-responsive kinase-1 phosphorylate downstream NKCC2 and NCC to maintain Na+ and blood pressure (BP) homeostasis. Mammalian Ste20 kinase 3 (MST3) is another member of the Ste20 family. We previously reported that reduced MST3 levels were found in the kidneys in spontaneously hypertensive rats and that MST3 was involved in Na+ regulation. To determine whether MST3 is involved in BP stability through Na+ regulation, we generated a MST3 hypomorphic mutation and designated MST3+/− and MST3−/− mice to examine BP and serum Na+ and K+ concentrations. MST3−/− mice exhibited hypernatremia, hypokalemia, and hypertension. The increased ENaC in the kidney played roles in hypernatremia. The reabsorption of more Na+ promoted more K+ secretion in the kidney and caused hypokalemia. The hypernatremia and hypokalemia in MST3−/− mice were significantly reversed by the ENaC inhibitor amiloride, indicating that MST3−/− mice reabsorbed more Na+ through ENaC. Furthermore, Madin-Darby canine kidney cells stably expressing kinase-dead MST3 displayed elevated ENaC currents. Both the in vivo and in vitro results indicated that MST3 maintained Na+ homeostasis through ENaC regulation. We are the first to report that MST3 maintains BP stability through ENaC regulation.

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