scholarly journals Sendai-viral HN and F glycoproteins as probes of plasma-membrane protein catabolism in HTC cells. Studies with fusogenic reconstituted Sendai-viral envelopes

1987 ◽  
Vol 241 (3) ◽  
pp. 801-807 ◽  
Author(s):  
R T Earl ◽  
E E Billett ◽  
I M Hunneyball ◽  
R J Mayer
Keyword(s):  
Plasma Membrane ◽  
Membrane Protein ◽  
Plasma Membranes ◽  
Viral Proteins ◽  
Plasma Membrane Protein ◽  
Lysosomal Degradation ◽  
Cell Plasma ◽  
Degradation Rates ◽  
Htc Cells ◽  
Viral Envelopes

Reconstituted Sendai-viral envelopes (RSVE) were produced by the method of Vainstein, Hershkovitz, Israel & Loyter [(1984) Biochim. Biophys. Acta 773, 181-188]. RSVE are fusogenic unilamellar vesicles containing two transmembrane glycoproteins: the HN (haemagglutinin-neuraminidase) protein and the F (fusion) factor. The fate of the viral proteins after fusion-mediated transplantation of RSVE into hepatoma (HTC) cell plasma membranes was studied to probe plasma-membrane protein degradation. Both protein species are degraded at similar, relatively slow, rates (t1/2 = 67 h) in HTC cells fused with RSVE in suspension. Even slower degradation rates for HN and F proteins (t1/2 = 93 h) were measured when RSVE were fused with HTC cells in monolayer. Lysosomal degradation of the transplanted viral proteins is strongly implicated by the finding that degradation of HN and F proteins is sensitive to inhibition by 10 mM-NH4Cl (81%) and by 50 micrograms of leupeptin/ml (70%).

scholarly journals Proteomics Analysis of Plasma Membrane Fractions of the Root, Leaf, and Flower of Rice

2020 ◽  
Vol 21 (19) ◽  
pp. 6988
Author(s):  
Yukimoto Iwasaki ◽  
Takafumi Itoh ◽  
Yusuke Hagi ◽  
Sakura Matsuta ◽  
Aki Nishiyama ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Protein ◽  
Plasma Membranes ◽  
Cell Function ◽  
Immunoblot Analysis ◽  
Leaf Sheath ◽  
Green Leaf ◽  
Organ Specificity ◽  
Plasma Membrane Protein ◽  
Proteomics Data

The plasma membrane regulates biological processes such as ion transport, signal transduction, endocytosis, and cell differentiation/proliferation. To understand the functional characteristics and organ specificity of plasma membranes, plasma membrane protein fractions from rice root, etiolated leaf, green leaf, developing leaf sheath, and flower were analyzed by proteomics. Among the proteins identified, 511 were commonly accumulated in the five organs, whereas 270, 132, 359, 146, and 149 proteins were specifically accumulated in the root, etiolated leaf, green leaf, developing leaf sheath, and developing flower, respectively. The principle component analysis revealed that the functions of the plasma membrane in the root was different from those of green and etiolated leaves and that the plasma membrane protein composition of the leaf sheath was similar to that of the flower, but not that of the green leaf. Functional classification revealed that the root plasma membrane has more transport-related proteins than the leaf plasma membrane. Furthermore, the leaf sheath and flower plasma membranes were found to be richer in proteins involved in signaling and cell function than the green leaf plasma membrane. To validate the proteomics data, immunoblot analysis was carried out, focusing on four heterotrimeric G protein subunits, Gα, Gβ, Gγ1, and Gγ2. All subunits could be detected by both methods and, in particular, Gγ1 and Gγ2 required concentration by immunoprecipitation for mass spectrometry detection.

scholarly journals A plasma membrane protein is involved in cell contact-mediated regulation of tissue-specific genes in adult hepatocytes.

1991 ◽  
Vol 115 (2) ◽  
pp. 505-515 ◽  
Author(s):  
A Corlu ◽  
B Kneip ◽  
C Lhadi ◽  
G Leray ◽  
D Glaise ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Plasma Membrane ◽  
Membrane Protein ◽  
Plasma Membranes ◽  
Surface Protein ◽  
Cell Aggregation ◽  
Cell Interaction ◽  
Cell Contact ◽  
Plasma Membrane Protein ◽  
Extracellular Matrix Components

We have identified the liver-regulating protein (LRP), a cell surface protein involved in the maintenance of hepatocyte differentiation when cocultured with rat liver epithelial cells (RLEC). LRP was defined by immunoreactivity to a monoclonal antibody (mAb L8) prepared from RLEC. mAb L8 specifically detected two polypeptides of 85 and 73 kD in immunoprecipitation of both hepatocyte- and RLEC-iodinated plasma membranes. The involvement of these polypeptides, which are integral membrane proteins, in cell interaction-mediated regulation of hepatocytes was assessed by evaluating the perturbing effects of the antibody on cocultures with RLEC. Several parameters characteristic of differentiated hepatocytes were studied, such as liver-specific and house-keeping gene expression, cytoskeletal organization and deposition of extracellular matrix (ECM). An early cytoskeletal disturbance was evidenced and a marked alteration of hepatocyte functional capacity was observed in the presence of the antibody, together with a loss of ECM deposition. By contrast, cell-cell aggregation or cell adhesion to various extracellular matrix components were not affected. These findings suggest that LRP is distinct from an extracellular matrix receptor. The fact that early addition of mAb L8 during cell contact establishment was necessary to be effective may indicate that LRP is a novel plasma membrane protein that plays an early pivotal role in the coordinated metabolic changes which lead to the differentiated phenotype of mature hepatocytes.

scholarly journals A 39-kD plasma membrane protein (IP39) is an anchor for the unusual membrane skeleton of Euglena gracilis.

1990 ◽  
Vol 110 (4) ◽  
pp. 1077-1088 ◽  
Author(s):  
T K Rosiere ◽  
J A Marrs ◽  
G B Bouck
Keyword(s):  
Plasma Membrane ◽  
Membrane Protein ◽  
Cell Surface ◽  
Euglena Gracilis ◽  
Plasma Membranes ◽  
Membrane Skeleton ◽  
Surface Proteins ◽  
Plasma Membrane Protein ◽  
Octyl Glucoside ◽  
Skeletal Protein

The major integral plasma membrane protein (IP39) of Euglena gracilis was radiolabeled, peptide mapped, and dissected with proteases to identify cytoplasmic domains that bind and anchor proteins of the cell surface. When plasma membranes were radioiodinated and extracted with octyl glucoside, 98% of the extracted label was found in IP39 or the 68- and 110-kD oligomers of IP39. The octyl glucoside extracts were incubated with unlabeled cell surface proteins immobilized on nitrocellulose (overlays). Radiolabel from the membrane extract bound one (80 kD) of the two (80 and 86 kD) major membrane skeletal protein bands. Resolubilization of the bound label yielded a radiolabeled polypeptide identical in Mr to IP39. Intact plasma membranes were also digested with papain before or after radioiodination, thereby producing a cytoplasmically truncated IP39. The octyl glucoside extract of truncated IP39 no longer bound to the 80-kD membrane skeletal protein in the nitrocellulose overlays. EM of intact or trypsin digested plasma membranes incubated with membrane skeletal proteins under stringent conditions similar to those used in the nitrocellulose overlays revealed a partially reformed membrane skeletal layer. Little evidence of a membrane skeletal layer was found, however, when plasma membranes were predigested with papain before reassociation. A candidate 80-kD binding domain of IP39 has been tentatively identified as a peptide fragment that was present after trypsin digestion of plasma membranes, but was absent after papain digestion in two-dimensional peptide maps of IP39. Together, these data suggest that the unique peripheral membrane skeleton of Euglena binds to the plasma membrane through noncovalent interactions between the major 80-kD membrane skeletal protein and a small, papain sensitive cytoplasmic domain of IP39. Other (62, 51, and 25 kD) quantitatively minor peripheral proteins also interact with IP39 on the nitrocellulose overlays, and the possible significance of this binding is discussed.

scholarly journals Structural Organization of the Lens Fiber Cell Plasma Membrane Protein MP18

1989 ◽  
Vol 264 (33) ◽  
pp. 19974-19978 ◽  
Author(s):  
A Galvan ◽  
P D Lampe ◽  
K C Hur ◽  
J B Howard ◽  
E D Eccleston ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Protein ◽  
Structural Organization ◽  
Fiber Cell ◽  
Lens Fiber ◽  
Plasma Membrane Protein ◽  
Cell Plasma Membrane ◽  
Lens Fiber Cell ◽  
Cell Plasma
Sign in / Sign up

Export Citation Format

Share Document