Restricted lateral diffusion of PH-20, a PI-anchored sperm membrane protein

Science ◽  
1988 ◽  
Vol 240 (4860) ◽  
pp. 1780-1782 ◽  
Author(s):  
BM Phelps ◽  
P Primakoff ◽  
DE Koppel ◽  
MG Low ◽  
DG Myles
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Diffusion Rate ◽  
Lateral Diffusion ◽  
Surface Protein ◽  
Integral Membrane Proteins ◽  
Testicular Sperm ◽  
Lateral Mobility ◽  
Sperm Membrane ◽  
Lipid Diffusion

The rate of lateral diffusion of integral membrane proteins is constrained in cells, but the constraining factors for most membrane proteins have not been defined. PH-20, a sperm surface protein involved in sperm-egg adhesion, was shown to be anchored in the plasma membrane by attachment to the lipid phosphatidylinositol and to have a diffusion rate that is highly restricted on testicular sperm, being more than a thousand times slower than lipid diffusion. These results support the hypothesis that lateral mobility of a membrane protein can be regulated exclusively by interactions of its ectodomain.

scholarly journals Scratching the surface: native mass spectrometry of peripheral membrane protein complexes

2020 ◽  
Vol 48 (2) ◽  
pp. 547-558 ◽  
Author(s):  
Cagla Sahin ◽  
Deseree J. Reid ◽  
Michael T. Marty ◽  
Michael Landreh
Keyword(s):  
Mass Spectrometry ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Lipid Vesicles ◽  
Native Mass Spectrometry ◽  
Integral Membrane Proteins ◽  
Structural Basis ◽  
Lipid Interactions ◽  
Native Ms ◽  
Peripheral Membrane Protein

A growing number of integral membrane proteins have been shown to tune their activity by selectively interacting with specific lipids. The ability to regulate biological functions via lipid interactions extends to the diverse group of proteins that associate only peripherally with the lipid bilayer. However, the structural basis of these interactions remains challenging to study due to their transient and promiscuous nature. Recently, native mass spectrometry has come into focus as a new tool to investigate lipid interactions in membrane proteins. Here, we outline how the native MS strategies developed for integral membrane proteins can be applied to generate insights into the structure and function of peripheral membrane proteins. Specifically, native MS studies of proteins in complex with detergent-solubilized lipids, bound to lipid nanodiscs, and released from native-like lipid vesicles all shed new light on the role of lipid interactions. The unique ability of native MS to capture and interrogate protein–protein, protein–ligand, and protein–lipid interactions opens exciting new avenues for the study of peripheral membrane protein biology.

scholarly journals Method for Recovery and Immunoaffinity Enrichment of Membrane Proteins Illustrated with Metastatic Ovarian Cancer Tissues

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Luke V. Schneider ◽  
Varsha Likhte ◽  
William H. Wright ◽  
Frances Chu ◽  
Emma Cambron ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Integral Membrane Proteins ◽  
Buffer System ◽  
Western Blots ◽  
Pathogen Invasion ◽  
Quantitative Extraction ◽  
Extraction Buffer ◽  
Pressure Cycling Technology ◽  
Cancer Tissues

Integral membrane proteins play key biological roles in cell signaling, transport, and pathogen invasion. However, quantitative clinical assays for this critical class of proteins remain elusive and are generally limited to serum-soluble extracellular fragments. Furthermore, classic proteomic approaches to membrane protein analysis typically involve proteolytic digestion of the soluble pieces, resulting in separation of intra- and extracellular segments and significant informational loss. In this paper, we describe the development of a new method for the quantitative extraction of intact integral membrane proteins (including GPCRs) from solid metastatic ovarian tumors using pressure cycling technology in combination with a new (ProteoSolve-TD) buffer system. This new extraction buffer is compatible with immunoaffinity methods (e.g., ELISA and immunoaffinity chromatography), as well as conventional proteomic techniques (e.g., 2D gels, western blots). We demonstrate near quantitative recovery of membrane proteins EDG2, EDG4, FASLG, KDR, and LAMP-3 by western blots. We have also adapted commercial ELISAs for serum-soluble membrane protein fragments (e.g., sVEGFR2) to measure the tissue titers of their transmembrane progenitors. Finally, we demonstrate the compatibility of the new buffers with immunoaffinity enrichment/mass spectrometric characterization of tissue proteins.

scholarly journals Membrane Protein Degradation by FtsH Can Be Initiated from Either End

2002 ◽  
Vol 184 (17) ◽  
pp. 4775-4782 ◽  
Author(s):  
Shinobu Chiba ◽  
Yoshinori Akiyama ◽  
Koreaki Ito
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Exact Sequence ◽  
Integral Membrane Proteins ◽  
Amino Acid Residues ◽  
Aaa Atpase ◽  
Membrane Bound ◽  
Periplasmic Domain

ABSTRACT FtsH, a membrane-bound metalloprotease, with cytoplasmic metalloprotease and AAA ATPase domains, degrades both soluble and integral membrane proteins in Escherichia coli. In this paper we investigated how membrane-embedded substrates are recognized by this enzyme. We showed previously that FtsH can initiate processive proteolysis at an N-terminal cytosolic tail of a membrane protein, by recognizing its length (more than 20 amino acid residues) but not exact sequence. Subsequent proteolysis should involve dislocation of the substrates into the cytosol. We now show that this enzyme can also initiate proteolysis at a C-terminal cytosolic tail and that the initiation efficiency depends on the length of the tail. This mode of degradation also appeared to be processive, which can be aborted by a tightly folded periplasmic domain. These results indicate that FtsH can exhibit processivity against membrane-embedded substrates in either the N-to-C or C-to-N direction. Our results also suggest that some membrane proteins receive bidirectional degradation simultaneously. These results raise intriguing questions about the molecular directionality of the dislocation and proteolysis catalyzed by FtsH.

scholarly journals Selection of Biophysical Methods for Characterisation of Membrane Proteins

2019 ◽  
Vol 20 (10) ◽  
pp. 2605 ◽  
Author(s):  
Tristan O. C. Kwan ◽  
Rosana Reis ◽  
Giuliano Siligardi ◽  
Rohanah Hussain ◽  
Harish Cheruvara ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Early Stage ◽  
Biological Membrane ◽  
Basic Research ◽  
Integral Membrane Protein ◽  
Integral Membrane Proteins ◽  
Functional Protein ◽  
Protein Research ◽  
Selection Of

Over the years, there have been many developments and advances in the field of integral membrane protein research. As important pharmaceutical targets, it is paramount to understand the mechanisms of action that govern their structure–function relationships. However, the study of integral membrane proteins is still incredibly challenging, mostly due to their low expression and instability once extracted from the native biological membrane. Nevertheless, milligrams of pure, stable, and functional protein are always required for biochemical and structural studies. Many modern biophysical tools are available today that provide critical information regarding to the characterisation and behaviour of integral membrane proteins in solution. These biophysical approaches play an important role in both basic research and in early-stage drug discovery processes. In this review, it is not our objective to present a comprehensive list of all existing biophysical methods, but a selection of the most useful and easily applied to basic integral membrane protein research.

scholarly journals Stitching proteins into membranes, not sew simple

2014 ◽  
Vol 395 (12) ◽  
pp. 1417-1424 ◽  
Author(s):  
Paul Whitley ◽  
Ismael Mingarro
Keyword(s):  
Endoplasmic Reticulum ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Protein Assembly ◽  
Integral Membrane Proteins ◽  
Eukaryotic Cells ◽  
Endomembrane System ◽  
Correct Orientation ◽  
Tm Domain ◽  
Er Membrane

Abstract Most integral membrane proteins located within the endomembrane system of eukaryotic cells are first assembled co-translationally into the endoplasmic reticulum (ER) before being sorted and trafficked to other organelles. The assembly of membrane proteins is mediated by the ER translocon, which allows passage of lumenal domains through and lateral integration of transmembrane (TM) domains into the ER membrane. It may be convenient to imagine multi-TM domain containing membrane proteins being assembled by inserting their first TM domain in the correct orientation, with subsequent TM domains inserting with alternating orientations. However a simple threading model of assembly, with sequential insertion of one TM domain into the membrane after another, does not universally stand up to scrutiny. In this article we review some of the literature illustrating the complexities of membrane protein assembly. We also present our own thoughts on aspects that we feel are poorly understood. In short we hope to convince the readers that threading of membrane proteins into membranes is ‘not sew simple’ and a topic that requires further investigation.

Comparison of lipidic carrier systems for integral membrane proteins – MsbA as case study

2019 ◽  
Vol 400 (11) ◽  
pp. 1509-1518 ◽  
Author(s):  
Dominique-Maurice Kehlenbeck ◽  
Inokentijs Josts ◽  
Julius Nitsche ◽  
Sebastian Busch ◽  
V. Trevor Forsyth ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Integral Membrane Proteins ◽  
Structural Studies ◽  
Long Term Stability ◽  
Activity Measurements ◽  
Protein Research ◽  
Protein Instability ◽  
Lipid Nanodiscs ◽  
Carrier Systems

Abstract Membrane protein research suffers from the drawback that detergents, which are commonly used to solubilize integral membrane proteins (IMPs), often lead to protein instability and reduced activity. Recently, lipid nanodiscs (NDs) and saposin-lipoprotein particles (Salipro) have emerged as alternative carrier systems that keep membrane proteins in a native-like lipidic solution environment and are suitable for biophysical and structural studies. Here, we systematically compare nanodiscs and Salipros with respect to long-term stability as well as activity and stability of the incorporated membrane protein using the ABC transporter MsbA as model system. Our results show that both systems are suitable for activity measurements as well as structural studies in solution. Based on our results we suggest screening of different lipids with respect to activity and stability of the incorporated IMP before performing structural studies.

Lateral mobility of human erythrocyte integral membrane proteins

Nature ◽  
1977 ◽  
Vol 268 (5615) ◽  
pp. 23-26 ◽  
Author(s):  
Velia Fowler ◽  
Daniel Branton
Keyword(s):  
Membrane Proteins ◽  
Human Erythrocyte ◽  
Integral Membrane Proteins ◽  
Lateral Mobility
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