scholarly journals Purification of a cortisol binding protein from hepatic plasma membrane

1996 ◽  
Vol 1284 (1) ◽  
pp. 41-46 ◽  
Author(s):  
Iñaki Ibarrola ◽  
Miriam Andrés ◽  
Aída Marino ◽  
JoséM. Macarulla ◽  
Miguel Trueba
Keyword(s):  
Plasma Membrane ◽  
Binding Protein

scholarly journals Redistribution of a rab3-like GTP-binding protein from secretory granules to the Golgi complex in pancreatic acinar cells during regulated exocytosis

1994 ◽  
Vol 124 (1) ◽  
pp. 43-53 ◽  
Author(s):  
BP Jena ◽  
FD Gumkowski ◽  
EM Konieczko ◽  
GF von Mollard ◽  
R Jahn ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Golgi Complex ◽  
Binding Protein ◽  
Secretory Granules ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Apical Plasma Membrane ◽  
Gtp Binding Protein ◽  
Regulated Exocytosis ◽  
Gtp Binding

Regulated secretion from pancreatic acinar cells occurs by exocytosis of zymogen granules (ZG) at the apical plasmalemma. ZGs originate from the TGN and undergo prolonged maturation and condensation. After exocytosis, the zymogen granule membrane (ZGM) is retrieved from the plasma membrane and ultimately reaches the TGN. In this study, we analyzed the fate of a low M(r) GTP-binding protein during induced exocytosis and membrane retrieval using immunoblots as well as light and electron microscopic immunocytochemistry. This 27-kD protein, identified by a monoclonal antibody that recognizes rab3A and B, may be a novel rab3 isoform. In resting acinar cells, the rab3-like protein was detected primarily on the cytoplasmic face of ZGs, with little labeling of the Golgi complex and no significant labeling of the apical plasmalemma or any other intracellular membranes. Stimulation of pancreatic lobules in vitro by carbamylcholine for 15 min, resulted in massive exocytosis that led to a near doubling of the area of the apical plasma membrane. However, no relocation of the rab3-like protein to the apical plasmalemma was seen. After 3 h of induced exocytosis, during which time approximately 90% of the ZGs is released, the rab3-like protein appeared to translocate to small vesicles and newly forming secretory granules in the TGN. No significant increase of the rab3-like protein was found in the cytosolic fraction at any time during stimulation. Since the protein is not detected on the apical plasmalemma after stimulation, we conclude that recycling may involve a membrane dissociation-association cycle that accompanies regulated exocytosis.

scholarly journals Munc13-4 Is a Rab11-binding Protein That Regulates Rab11-positive Vesicle Trafficking and Docking at the Plasma Membrane

2015 ◽  
Vol 291 (7) ◽  
pp. 3423-3438 ◽  
Author(s):  
Jennifer L. Johnson ◽  
Jing He ◽  
Mahalakshmi Ramadass ◽  
Kersi Pestonjamasp ◽  
William B. Kiosses ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Binding Protein ◽  
Vesicle Trafficking

Developmentally regulated expression of insulin-like growth factors by differentiated murine teratocarcinomas and extraembryonic mesoderm

Development ◽  
1986 ◽  
Vol 95 (1) ◽  
pp. 193-212
Author(s):  
John K. Heath ◽  
Wai-Kang Shi
Keyword(s):  
Plasma Membrane ◽  
Binding Protein ◽  
Membrane Receptors ◽  
Developmentally Regulated ◽  
Igf Receptors ◽  
Igf Binding ◽  
Plasma Membrane Receptors ◽  
Igf Binding Protein ◽  
Culture Supernatants ◽  
Insulin Like Growth Factors

The expression of plasma membrane receptors for insulin-like growth factors (IGFs) by PC13 embryonal carcinoma (EC) cells, and their immediate differentiated progeny PC13END was examined by binding radiolabelled IGF-I to cell monolayers. Both cell types express high-affinity IGF receptors, but the apparent number of unoccupied receptor sites falls by about 60% upon differentiation. Crosslinking studies reveal that both type 1 and type 2 IGF receptors are expressed by PC13EC cells. PC13END-cell-conditioned medium contains developmentally regulated, separable activities, one of which reacts directly with IGF-II, and the other with IGF for plasma membrane receptors. The former activity represents a soluble secreted IGF-binding protein. The latter activity is structurally and functionally similar to rat IGF-II. Polyclonal antibodies raised against purified rat IGF-II specifically recognize multiple forms of IGF in radiolabelled culture supernatants and material which closely resembles the soluble IGF-binding protein. Immunoprecipitation of radiolabelled culture supernatants with anti-rat IGF-II reveals that the differentiation of PC13EC cells is accompanied by the coexpression of IGF-like molecules and the soluble binding protein, and that IGF-like molecules are expressed by extraembryonic tissues of mesodermal origin in the early postimplantation mouse embryo. These findings show that IGF-like molecules are expressed in early mammalian development and may act in an autocrine fashion in vivo.

scholarly journals Penicillin-binding proteins and carboxypeptidase/transpeptidase activities in Proteus vulgaris P18 and its penicillin-induced stable L-forms

1982 ◽  
Vol 152 (3) ◽  
pp. 1042-1048
Author(s):  
A Rousset ◽  
M Nguyen-Distèche ◽  
R Minck ◽  
J M Ghuysen
Keyword(s):  
Plasma Membrane ◽  
Binding Proteins ◽  
Binding Protein ◽  
Penicillin Binding Protein ◽  
Proteus Vulgaris ◽  
Penicillin Binding Proteins

The originally penicillin-induced, wall-less stable L-forms of Proteus vulgaris P18, isolated by Tulasne in 1949 and since then cultured in he absence of penicillin, have kept the ability to synthesize the seven penicillin-binding proteins and the various DD- and LD-peptidase activities found in the parental bacteria and known to be involved in wall peptidoglycan metabolism. The stable L-forms, however, secrete during growth both the highly penicillin-sensitive, DD-carboxy-peptidase-transpeptidase penicillin-binding protein PBP4 (which in normal bacteria is relatively loosely bound to the plasma membrane) and the penicillin-insensitive LD-carboxypeptidase (which in normal bacteria is located in the periplasmic region).

Internalization and intracellular transport of folate-binding protein in rat kidney proximal tubule

1993 ◽  
Vol 264 (2) ◽  
pp. C302-C310 ◽  
Author(s):  
H. Birn ◽  
J. Selhub ◽  
E. I. Christensen
Keyword(s):  
Plasma Membrane ◽  
Proximal Tubule ◽  
Brush Border ◽  
Intracellular Transport ◽  
Brush Border Membrane ◽  
Specific Binding ◽  
Binding Protein ◽  
Rat Kidney ◽  
Folate Binding Protein

Folate-binding protein (FBP) is involved in folate reabsorption in the renal proximal tubule. Immunocytochemical studies have located FBP to the brush-border membrane, endocytic vacuoles, and dense apical tubules. We applied the same polyclonal antibody (anti-FBP) against FBP to investigate the dynamic relationship between FBP in the different compartments by microinjecting the antibody into rat kidney proximal tubules in situ. Specific binding of anti-FBP in vivo to the brush-border membrane was followed by fixation at various times. Protein A-gold labeling shows that anti-FBP is transported from endocytic invaginations into vacuoles followed by transport into dense apical tubules within 15 s. Thus FBP is rapidly internalized, and together with previous studies this study strongly suggests recycling of FBP back to the luminal plasma membrane through dense apical tubules. The results are consistent with reabsorption of folate through endocytosis of the FBP-folate complex followed by dissociation and recycling of FBP. When time is allowed there is a steady accumulation of FBP in dense apical tubules combined with an increase in surface density of the same compartment. A possible explanation involves partial inhibition of the fusion between dense apical tubules and plasma membrane because of the anti-FBP labeling of the receptor.

scholarly journals Release of C8 binding protein (C8bp) from the cell membrane by phosphatidylinositol-specific phospholipase C

Blood ◽  
1988 ◽  
Vol 72 (3) ◽  
pp. 1089-1092
Author(s):  
GM Hansch ◽  
PF Weller ◽  
A Nicholson-Weller
Keyword(s):  
Plasma Membrane ◽  
Cell Membrane ◽  
Phospholipase C ◽  
Paroxysmal Nocturnal Hemoglobinuria ◽  
Binding Protein ◽  
Regulatory Proteins ◽  
Membrane Expression ◽  
Normal Cells ◽  
Complement Regulatory Proteins ◽  
Common Defect

Abstract Erythrocytes from patients with paroxysmal nocturnal hemoglobinuria (PNH) are abnormally sensitive to complement. Two membrane proteins, the C8 binding protein (C8bp) and the decay accelerating factor (DAF), which are expressed on normal cells, function to restrict lysis by homologous complement, and both of these proteins are absent from PNH erythrocytes. DAF is anchored to the plasma membrane on normal cells by a phosphatidylinositol linkage. The investigators found that a purified phosphatidylinositol-specific phospholipase C cleaved C8bp from the surface of normal lymphocytes and monocytes. This finding indicates that the abnormal complement sensitivity of PNH erythrocytes arises from a common defect, the inability to attach the phosphatidylinositol- containing anchor that is necessary for the membrane expression of both membrane complement regulatory proteins, the C8bp, and DAF.

scholarly journals gp96 Is a Human Colonocyte Plasma Membrane Binding Protein for Clostridium difficile Toxin A

2008 ◽  
Vol 76 (7) ◽  
pp. 2862-2871 ◽  
Author(s):  
Xi Na ◽  
Ho Kim ◽  
Mary P. Moyer ◽  
Charalabos Pothoulakis ◽  
J. Thomas LaMont
Keyword(s):  
Plasma Membrane ◽  
Clostridium Difficile ◽  
Binding Protein ◽  
Membrane Binding ◽  
Cell Surface Receptor ◽  
Toxin A ◽  
Surface Receptor ◽  
A Cell ◽  
Plasma Membrane Binding

ABSTRACT Clostridium difficile toxin A (TxA), a key mediator of antibiotic-associated colitis, requires binding to a cell surface receptor prior to internalization. Our aim was to identify novel plasma membrane TxA binding proteins on human colonocytes. TxA was coupled with biotin and cross-linked to the surface of HT29 human colonic epithelial cells. The main colonocyte binding protein for TxA was identified as glycoprotein 96 (gp96) by coimmunoprecipitation and mass spectrum analysis. gp96 is a member of the heat shock protein family, which is expressed on human colonocyte apical membranes as well as in the cytoplasm. TxA binding to gp96 was confirmed by fluorescence immunostaining and in vitro coimmunoprecipitation. Following TxA binding, the TxA-gp96 complex was translocated from the cell membrane to the cytoplasm. Pretreatment with gp96 antibody decreased TxA binding to colonocytes and inhibited TxA-induced cell rounding. Small interfering RNA directed against gp96 reduced gp96 expression and cytotoxicity in colonocytes. TxA-induced inflammatory signaling via p38 and apoptosis as measured by activation of BAK (Bcl-2 homologous antagonist/killer) and DNA fragmentation were decreased in gp96-deficient B cells. We conclude that human colonocyte gp96 serves as a plasma membrane binding protein that enhances cellular entry of TxA, participates in cellular signaling events in the inflammatory cascade, and facilitates cytotoxicity.

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