Ist2 recruits the lipid transporters Osh6/7 to ER–PM contacts to maintain phospholipid metabolism

2021 ◽  
Vol 220 (9) ◽  
Author(s):  
Andrew King On Wong ◽  
Barry Paul Young ◽  
Christopher J.R. Loewen
Keyword(s):  
Plasma Membrane ◽  
Binding Site ◽  
Family Members ◽  
Phospholipid Metabolism ◽  
Transport Proteins ◽  
Lipid Transporters

ER-plasma membrane (PM) contacts are proposed to be held together by distinct families of tethering proteins, which in yeast include the VAP homologues Scs2/22, the extended-synaptotagmin homologues Tcb1/2/3, and the TMEM16 homologue Ist2. It is unclear whether these tethers act redundantly or whether individual tethers have specific functions at contacts. Here, we show that Ist2 directly recruits the phosphatidylserine (PS) transport proteins and ORP family members Osh6 and Osh7 to ER–PM contacts through a binding site located in Ist2’s disordered C-terminal tethering region. This interaction is required for phosphatidylethanolamine (PE) production by the PS decarboxylase Psd2, whereby PS transported from the ER to the PM by Osh6/7 is endocytosed to the site of Psd2 in endosomes/Golgi/vacuoles. This role for Ist2 and Osh6/7 in nonvesicular PS transport is specific, as other tethers/transport proteins do not compensate. Thus, we identify a molecular link between the ORP and TMEM16 families and a role for endocytosis of PS in PE synthesis.

Elementary auxin response chains at the plasma membrane involve external abp1 and multiple electrogenic ion transport proteins

1996 ◽  
Vol 18 (1-2) ◽  
pp. 23-28 ◽  
Author(s):  
H�l�ne Barbier-Brygoo ◽  
Sabine Zimmermann ◽  
S�bastien Thomine ◽  
Ian R. White ◽  
Paul Millner ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Ion Transport ◽  
Transport Proteins ◽  
Auxin Response ◽  
Electrogenic Ion Transport ◽  
Response Chains

Inhibition of clathrin-coated pit assembly by an Eps15 mutant

1999 ◽  
Vol 112 (9) ◽  
pp. 1303-1311 ◽  
Author(s):  
A. Benmerah ◽  
M. Bayrou ◽  
N. Cerf-Bensussan ◽  
A. Dautry-Varsat
Keyword(s):  
Plasma Membrane ◽  
Fusion Protein ◽  
Binding Site ◽  
Specific Marker ◽  
Coated Pits ◽  
Receptor Mediated Endocytosis ◽  
Gfp Fusion Protein ◽  
Protein Encoding ◽  
Homology Domains

Recent data have shown that Eps15, a newly identified component of clathrin-coated pits constitutively associated with the AP-2 complex, is required for receptor-mediated endocytosis. However, its precise function remains unknown. Interestingly, Eps15 contains three EH (Eps15-Homology) domains also found in proteins required for the internalization step of endocytosis in yeast. Results presented here show that EH domains are required for correct coated pit targeting of Eps15. Furthermore, when cells expressed an Eps15 mutant lacking EH domains, the plasma membrane punctate distribution of both AP-2 and clathrin was lost, implying the absence of coated pits. This was further confirmed by the fact that dynamin, a GTPase found in coated pits, was homogeneously redistributed on the plasma membrane and that endocytosis of transferrin, a specific marker of clathrin-dependent endocytosis, was strongly inhibited. Altogether, these results strongly suggest a role for Eps15 in coated pit assembly and more precisely a role for Eps15 in the docking of AP-2 onto the plasma membrane. This hypothesis is supported by the fact that a GFP fusion protein encoding the ear domain of (alpha)-adaptin, the AP-2 binding site for Eps15, was efficiently targeted to plasma membrane coated pits.

Role of membrane trafficking in plasma membrane solute transport

1994 ◽  
Vol 267 (1) ◽  
pp. C1-C24 ◽  
Author(s):  
N. A. Bradbury ◽  
R. J. Bridges
Keyword(s):  
Plasma Membrane ◽  
Solute Transport ◽  
Membrane Trafficking ◽  
Molecular Mechanisms ◽  
Glucose Transporter ◽  
Water Channel ◽  
Transport Proteins ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Regulated Trafficking

Cells can rapidly and reversibly alter solute transport rates by changing the kinetics of transport proteins resident within the plasma membrane. Most notably, this can be brought about by reversible phosphorylation of the transporter. An additional mechanism for acute regulation of plasma membrane transport rates is by the regulated exocytic insertion of transport proteins from intracellular vesicles into the plasma membrane and their subsequent regulated endocytic retrieval. Over the past few years, the number of transporters undergoing this regulated trafficking has increased dramatically, such that what was once an interesting translocation of a few transporters has now become a widespread modality for regulating plasma membrane solute permeabilities. The aim of this article is to review the models proposed for the regulated trafficking of transport proteins and what lines of evidence should be obtained to document regulated exocytic insertion and endocytic retrieval of transport proteins. We highlight four transporters, the insulin-responsive glucose transporter, the antidiuretic hormone-responsive water channel, the urinary bladder H(+)-ATPase, and the cystic fibrosis transmembrane conductance regulator Cl- channel, and discuss the various approaches taken to document their regulated trafficking. Finally, we discuss areas of uncertainty that remain to be investigated concerning the molecular mechanisms involved in regulating the trafficking of proteins.

scholarly journals Binding Site for Chitin Oligosaccharides in the Soybean Plasma Membrane

2001 ◽  
Vol 126 (3) ◽  
pp. 1162-1173 ◽  
Author(s):  
R. Bradley Day ◽  
Mitsuo Okada ◽  
Yuki Ito ◽  
Koji Tsukada ◽  
Habib Zaghouani ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Binding Site

scholarly journals The Binding Site for Regulatory 14-3-3 Protein in Plant Plasma Membrane H+-ATPase

2003 ◽  
Vol 278 (43) ◽  
pp. 42266-42272 ◽  
Author(s):  
Anja T. Fuglsang ◽  
Jonas Borch ◽  
Katrine Bych ◽  
Thomas P. Jahn ◽  
Peter Roepstorff ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Binding Site ◽  
Plant Plasma Membrane

The Hyaluronate-Binding Site from the Plasma Membrane is Distinct from the Binding Protein Present in Brain

1987 ◽  
Vol 16 (3) ◽  
pp. 225-235 ◽  
Author(s):  
Charles B. Underhill ◽  
Guido Tarone ◽  
Annamaria T. Kausz
Keyword(s):  
Plasma Membrane ◽  
Binding Site ◽  
Binding Protein

scholarly journals Effect of hypokalemia on renal expression of the ammonia transporter family members, Rh B Glycoprotein and Rh C Glycoprotein, in the rat kidney

2011 ◽  
Vol 301 (4) ◽  
pp. F823-F832 ◽  
Author(s):  
Ki-Hwan Han ◽  
Hyun-Wook Lee ◽  
Mary E. Handlogten ◽  
Jesse M. Bishop ◽  
Moshe Levi ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Metabolic Alkalosis ◽  
Collecting Duct ◽  
Family Members ◽  
Ammonia Excretion ◽  
Intercalated Cells ◽  
Acid Base ◽  
Ammonia Metabolism ◽  
Transporter Family ◽  
Base Disorder

Hypokalemia is a common electrolyte disorder that increases renal ammonia metabolism and can cause the development of an acid-base disorder, metabolic alkalosis. The ammonia transporter family members, Rh B glycoprotein (Rhbg) and Rh C glycoprotein (Rhcg), are expressed in the distal nephron and collecting duct and mediate critical roles in acid-base homeostasis by facilitating ammonia secretion. In the current studies, the effect of hypokalemia on renal Rhbg and Rhcg expression was examined. Normal Sprague-Dawley rats received either K+-free or control diets for 2 wk. Rats receiving the K+-deficient diet developed hypokalemia and metabolic alkalosis associated with significant increases in both urinary ammonia excretion and urine pH. Rhcg expression increased in the outer medullary collecting duct (OMCD). In OMCD intercalated cells, hypokalemia resulted in more discrete apical Rhcg expression and a marked increase in apical plasma membrane immunolabel. In principal cells, in the OMCD, hypokalemia increased both apical and basolateral Rhcg immunolabel intensity. Cortical Rhcg expression was not detectably altered by immunohistochemistry, although there was a slight decrease in total expression by immunoblot analysis. Rhbg protein expression was decreased slightly in the cortex and not detectably altered in the outer medulla. We conclude that in rat OMCD, hypokalemia increases Rhcg expression, causes more polarized apical expression in intercalated cells, and increases both apical and basolateral expression in the principal cell. Increased plasma membrane Rhcg expression in response to hypokalemia in the rat, particularly in the OMCD, likely contributes to the increased ammonia excretion and thereby to the development of metabolic alkalosis.

scholarly journals The Calmodulin-binding Site of Sphingosine Kinase and Its Role in Agonist-dependent Translocation of Sphingosine Kinase 1 to the Plasma Membrane

2006 ◽  
Vol 281 (17) ◽  
pp. 11693-11701 ◽  
Author(s):  
Catherine M. Sutherland ◽  
Paul A. B. Moretti ◽  
Niamh M. Hewitt ◽  
Christopher J. Bagley ◽  
Mathew A. Vadas ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Binding Site ◽  
Sphingosine Kinase ◽  
Sphingosine Kinase 1 ◽  
Calmodulin Binding
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