Biogenesis and Topology of Integral Membrane Proteins:  Characterization of Lactose Permease−Chloramphenicol Acetyltransferase Hybrids†

Biochemistry ◽  
1996 ◽  
Vol 35 (33) ◽  
pp. 10872-10878 ◽  
Author(s):  
Adrian Zelazny ◽  
Eitan Bibi
Keyword(s):  
Membrane Proteins ◽  
Chloramphenicol Acetyltransferase ◽  
Integral Membrane Proteins ◽  
Lactose Permease ◽  
And Topology

Characterization of two integral membrane proteins located in the protein bodies of pumpkin seeds

1995 ◽  
Vol 28 (6) ◽  
pp. 1089-1101 ◽  
Author(s):  
Kaori Inoue ◽  
Yuka Takeuchi ◽  
Mikio Nishimura ◽  
Ikuko Hara-Nishimura
Keyword(s):  
Membrane Proteins ◽  
Integral Membrane Proteins ◽  
Protein Bodies ◽  
Pumpkin Seeds

Characterization of a polymorphic family of integral membrane proteins in promastigotes of different Leishmania species

1994 ◽  
Vol 67 (1) ◽  
pp. 103-113 ◽  
Author(s):  
Fiona M. Symons ◽  
Peter J. Murray ◽  
Hong Ji ◽  
Richard J. Simpson ◽  
Amelia H. Osborn ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Leishmania Species ◽  
Integral Membrane Proteins

Solubilization, Purification, and Characterization of Integral Membrane Proteins

2011 ◽  
pp. 317-360 ◽  
Author(s):  
Víctor Lórenz-Fonfría ◽  
Alex Perálvarez-Marín ◽  
Esteve Padrós ◽  
Tzvetana Lazarova
Keyword(s):  
Membrane Proteins ◽  
Integral Membrane Proteins ◽  
Purification And Characterization

scholarly journals Characterization of constitutive ER-phagy of excess membrane proteins

PLoS Genetics ◽  
2020 ◽  
Vol 16 (12) ◽  
pp. e1009255
Author(s):  
Zhanna Lipatova ◽  
Valeriya Gyurkovska ◽  
Sarah F. Zhao ◽  
Nava Segev
Keyword(s):  
Quality Control ◽  
Endoplasmic Reticulum ◽  
Membrane Proteins ◽  
Human Health ◽  
Mammalian Cells ◽  
Normal Growth ◽  
Integral Membrane Proteins ◽  
Yeast Cells ◽  
Cellular Proteins

Thirty percent of all cellular proteins are inserted into the endoplasmic reticulum (ER), which spans throughout the cytoplasm. Two well-established stress-induced pathways ensure quality control (QC) at the ER: ER-phagy and ER-associated degradation (ERAD), which shuttle cargo for degradation to the lysosome and proteasome, respectively. In contrast, not much is known about constitutive ER-phagy. We have previously reported that excess of integral-membrane proteins is delivered from the ER to the lysosome via autophagy during normal growth of yeast cells. Whereas endogenously expressed ER resident proteins serve as cargos at a basal level, this level can be induced by overexpression of membrane proteins that are not ER residents. Here, we characterize this pathway as constitutive ER-phagy. Constitutive and stress-induced ER-phagy share the basic macro-autophagy machinery including the conserved Atgs and Ypt1 GTPase. However, induction of stress-induced autophagy is not needed for constitutive ER-phagy to occur. Moreover, the selective receptors needed for starvation-induced ER-phagy, Atg39 and Atg40, are not required for constitutive ER-phagy and neither these receptors nor their cargos are delivered through it to the vacuole. As for ERAD, while constitutive ER-phagy recognizes cargo different from that recognized by ERAD, these two ER-QC pathways can partially substitute for each other. Because accumulation of membrane proteins is associated with disease, and constitutive ER-phagy players are conserved from yeast to mammalian cells, this process could be critical for human health.

Characterization of PrP binding proteins

1994 ◽  
Vol 343 (1306) ◽  
pp. 443-445 ◽  
Keyword(s):  
Membrane Proteins ◽  
Prion Protein ◽  
Binding Proteins ◽  
Mammalian Species ◽  
Integral Membrane Proteins ◽  
Infectious Particle ◽  
Spongiform Degeneration ◽  
The Brain ◽  
Total Membrane

Prions cause spongiform degeneration in various mammalian species. The scrapie prion protein (PrP Sc ) is part of the infectious particle and may mediate infection and spreading of the disease in the brain. It was therefore of interest to purify and analyse PrP ligands (Plis). Plis were identified on ligand blots using either intact PrP or peptides corresponding to the central portion of PrP. Here, characterization of a 110 and a 125 kDa Pli is reported. Both Plis were found in total membrane fractions and could be extracted with carbonate indicating that they are not integral membrane proteins. On sucrose gradients both PrP ligands sedimented with high density particles.

Thermodynamic Characterization of the Exchange of Detergents and Amphipols at the Surfaces of Integral Membrane Proteins

Langmuir ◽  
2009 ◽  
Vol 25 (21) ◽  
pp. 12623-12634 ◽  
Author(s):  
C. Tribet ◽  
C. Diab ◽  
T. Dahmane ◽  
M. Zoonens ◽  
J.-L. Popot ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Integral Membrane Proteins ◽  
Thermodynamic Characterization

Characterization of two antigenically related integral membrane proteins of the guinea pig sperm periacrosomal plasma membrane

1994 ◽  
Vol 39 (3) ◽  
pp. 309-321 ◽  
Author(s):  
V. Anne Westbrook-Case ◽  
Virginia P. Winfrey ◽  
Gary E. Olson
Keyword(s):  
Plasma Membrane ◽  
Membrane Proteins ◽  
Guinea Pig ◽  
Integral Membrane Proteins ◽  
Related Integral

The Effects of Increased Viscosity on the Function of Integral Membrane Proteins

1996 ◽  
Author(s):  
Suzanne F. Scarlata
Keyword(s):  
Activation Energy ◽  
Membrane Proteins ◽  
Active Site ◽  
Protein Function ◽  
Frequency Factor ◽  
Integral Membrane Proteins ◽  
Membrane Viscosity ◽  
Internal Motions ◽  
Soluble Enzymes

For many years the idea that the activity of integral membrane proteins is regulated by the fluidity of the lipid matrix was popular and appeared to be quite rational. However, as information about the effect of viscosity on the function of different membrane proteins became available, the correlation between the two became increasingly unclear. The purpose of this article is to readdress this issue in light of our recent pressure and temperature studies. This chapter is divided into seven parts: (1) the effect of viscosity on enzyme activity; (2) the effect of viscosity on the local motions of proteins; (3) characterization of membrane viscosity; (4) demonstration of changes in protein-lipid contacts brought about by changes in viscosity; (5) an example of a protein in which the viscosity appears to stabilize a particular conformational state: (6) relations between membrane viscosity and protein function; and (7) conclusions. The effect of viscosity (η) on the rate (k) of a chemical reaction was first given by Kramers (1940): . . . k=A/ηe−Ea/RT (1) . . . In this expression, viscosity will affect the rate of a reaction by limiting the rate of diffusion of reactants. Viscosity will thus modify the frequency factor (A) and should not affect the activation energy. This expression has been applied to aqueous soluble enzymes (for example, Gavish, 1979; Gavish & Werber, 1979; Somogyi et al., 1984), and it appears that, in general, enzymes obey Kramers’s relation, although in some cases the exponent of η is less than one. Viscosity can affect enzymatic rates not only by limiting the diffusion of substrates but also by damping internal motions of the protein chains. It seems reasonable that a high enough viscosities, the protein would be damped sufficiently so that large activation energies will be required for the backbone motions that allow substrates and products to diffuse into and out of the active site. This viscosity-induced increase in activation energy was shown by studies of the reassociation of carbon monoxide and dioxygen to the heme site of myoglobin after flash photodissociation (Austin et al., 1975; Beece et al., 1980).

Characterization of the human SDHC gene encoding one of the integral membrane proteins of succinate–quinone oxidoreductase in mitochondria

Gene ◽  
1998 ◽  
Vol 213 (1-2) ◽  
pp. 133-140 ◽  
Author(s):  
Amina Elbehti-Green ◽  
Harry C Au ◽  
James T Mascarello ◽  
Deena Ream-Robinson ◽  
Immo E Scheffler
Keyword(s):  
Membrane Proteins ◽  
Integral Membrane Proteins ◽  
Quinone Oxidoreductase ◽  
Gene Encoding

scholarly journals Capping of HLA antigens in human lymphocytes as followed by immunogold label-fracture.

1989 ◽  
Vol 37 (10) ◽  
pp. 1489-1496 ◽  
Author(s):  
A Pavan ◽  
P Mancini ◽  
M Cirone ◽  
L Frati ◽  
M R Torrisi ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Membrane Proteins ◽  
Human Lymphocytes ◽  
Hla Antigens ◽  
Integral Membrane Proteins ◽  
Immunogold Label ◽  
Intramembrane Particles

We used immunogold label-fracture to follow the migration of HLA I class and HLA II class antigens during capping as induced by specific monoclonal antibodies. Capping is achieved through a process of clustering and "consolidation" of clusters into larger patches and, finally, a single cap. All receptors appear to cluster from the very start, with no "stray" molecules joining already formed patches. Characterization of exoplasmic and protoplasmic fracture-faces of capping cells fails to reveal any corresponding accumulation of intramembrane particles and/or subtler rugosities. Our results are consistent with the concepts that view the migration of capping molecules as contemporaneous with the efflux of noncapping integral membrane proteins.

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