scholarly journals Membrane Profiling by Free Flow Electrophoresis and SWATH-MS to Characterize Subcellular Compartment Proteomes in Mesembryanthemum crystallinum

2021 ◽  
Vol 22 (9) ◽  
pp. 5020
Author(s):  
Qi Guo ◽  
Lei Liu ◽  
Won C. Yim ◽  
John C. Cushman ◽  
Bronwyn J. Barkla

The study of subcellular membrane structure and function facilitates investigations into how biological processes are divided within the cell. However, work in this area has been hampered by the limited techniques available to fractionate the different membranes. Free Flow Electrophoresis (FFE) allows for the fractionation of membranes based on their different surface charges, a property made up primarily of their varied lipid and protein compositions. In this study, high-resolution plant membrane fractionation by FFE, combined with mass spectrometry-based proteomics, allowed the simultaneous profiling of multiple cellular membranes from the leaf tissue of the plant Mesembryanthemum crystallinum. Comparisons of the fractionated membranes’ protein profile to that of known markers for specific cellular compartments sheds light on the functions of proteins, as well as provides new evidence for multiple subcellular localization of several proteins, including those involved in lipid metabolism.

Author(s):  
S. K. Pena ◽  
C. B. Taylor ◽  
J. Hill ◽  
J. Safarik

Introduction: Oxidized cholesterol derivatives have been demonstrated in various cell cultures to be very potent inhibitors of 3-hvdroxy-3- methylglutaryl Coenzyme A reductase which is a principle regulator of cholesterol biosynthesis in the cell. The cholesterol content in the cells exposed to oxidized cholesterol was found to be markedly decreased. In aortic smooth muscle cells, the potency of this effect was closely related to the cytotoxicity of each derivative. Furthermore, due to the similarity of their molecular structure to that of cholesterol, these oxidized cholesterol derivatives might insert themselves into the cell membrane, alter membrane structure and function and eventually cause cell death. Arterial injury has been shown to be the initial event of atherosclerosis.


1978 ◽  
Vol 39 (01) ◽  
pp. 177-185 ◽  
Author(s):  
Shuichi Hashimoto ◽  
Sachiko Shibata ◽  
Bonro Kobayashi

SummaryThe effect of Mitomycin C on aggregation, adenosine 3′, 5′-monophosphate (cyclic AMP) metabolism and reactions induced by thrombin was studied in rabbit platelets. Mitomycin C inhibited the platelet aggregation induced by adenosine diphosphate or thrombin. The level of radioactive cyclic AMP derived from 8-14C adenine or 8-14C adenosine increased after incubating intact platelets with Mitomycin G. Formation of radioactive adenosine triphosphate also increased though mitochondrial oxidation was not stimulated. Similar effect was observed also in rabbit liver. Mitomycin C failed to stimulate platelet adenyl cyclase but inhibited cyclic AMP phosphodiesterase in the absence of theophylline. In the platelets preincubated with Mitomycin C, thrombin-induced inhibition of adenyl cyclase, stimulation of membrane-bound cyclic AMP phosphodiesterase, and release of 250,000 dalton protein from platelet membranes were prevented. These results suggest that Mitomycin C will affect cellular membrane structure and function, and this extranuclear effect of Mitomycin C will lead to inhibition of aggregation in blood platelets.


2000 ◽  
Vol 20 (21) ◽  
pp. 7893-7902 ◽  
Author(s):  
Matthew E. Portnoy ◽  
Xiu Fen Liu ◽  
Valeria Cizewski Culotta

ABSTRACT The baker's yeast Saccharomyces cerevisiae expresses three homologues of the Nramp family of metal transporters: Smf1p, Smf2p, and Smf3p, encoded by SMF1, SMF2, andSMF3, respectively. Here we report a comparative analysis of the yeast Smf proteins at the levels of localization, regulation, and function of the corresponding metal transporters. Smf1p and Smf2p function in cellular accumulation of manganese, and the two proteins are coregulated by manganese ions and the BSD2 gene product. Under manganese-replete conditions, Bsd2p facilitates trafficking of Smf1p and Smf2p to the vacuole, where these transport proteins are degraded. However, Smf1p and Smf2p localize to distinct cellular compartments under metal starvation: Smf1p accumulates at the cell surface, while Smf2p is restricted to intracellular vesicles. The third Nramp homologue, Smf3p, is quite distinctive. Smf3p is not regulated by Bsd2p or by manganese ions and is not degraded in the vacuole. Instead, Smf3p is down-regulated by iron through a mechanism that does not involve transcription or protein stability. Smf3p localizes to the vacuolar membrane independently of metal treatment, and yeast cells lacking Smf3p show symptoms of iron starvation. We propose that Smf3p helps to mobilize vacuolar stores of iron.


Science ◽  
1975 ◽  
Vol 188 (4185) ◽  
pp. 282-282
Author(s):  
A. D. Keith ◽  
D. Deamer ◽  
J. K. Raison

Sign in / Sign up

Export Citation Format

Share Document