Cell-penetrating compounds preferentially bind glycosaminoglycans over plasma membrane lipids in a charge density- and stereochemistry-dependent manner

2015 ◽  
Vol 207 ◽  
pp. 40-50 ◽  
Author(s):  
Lisa E. Prevette ◽  
Nicolas C. Benish ◽  
Amber R. Schoenecker ◽  
Kristin J. Braden
Keyword(s):  
Plasma Membrane ◽  
Charge Density ◽  
Membrane Lipids ◽  
Dependent Manner ◽  
Cell Penetrating ◽  
A Charge

scholarly journals Oligomerization and Ca2+/calmodulin control binding of the ER Ca2+-sensors STIM1 and STIM2 to plasma membrane lipids

2013 ◽  
Vol 33 (5) ◽  
Author(s):  
Rajesh Bhardwaj ◽  
Hans-Michael Müller ◽  
Walter Nickel ◽  
Matthias Seedorf
Keyword(s):  
Plasma Membrane ◽  
Membrane Lipids ◽  
Lipid Binding ◽  
Dependent Manner ◽  
Activation Threshold ◽  
Concentration Dependent Manner ◽  
Rich Domain ◽  
Α Helix ◽  
Distinct Features ◽  
Ca2 Channels

Ca2+ (calcium) homoeostasis and signalling rely on physical contacts between Ca2+ sensors in the ER (endoplasmic reticulum) and Ca2+ channels in the PM (plasma membrane). STIM1 (stromal interaction molecule 1) and STIM2 Ca2+ sensors oligomerize upon Ca2+ depletion in the ER lumen, contact phosphoinositides at the PM via their cytosolic lysine (K)-rich domains, and activate Ca2+ channels. Differential sensitivities of STIM1 and STIM2 towards ER luminal Ca2+ have been studied but responses towards elevated cytosolic Ca2+ concentration and the mechanism of lipid binding remain unclear. We found that tetramerization of the STIM1 K-rich domain is necessary for efficient binding to PI(4,5)P2-containing PM-like liposomes consistent with an oligomerization-driven STIM1 activation. In contrast, dimerization of STIM2 K-rich domain was sufficient for lipid binding. Furthermore, the K-rich domain of STIM2, but not of STIM1, forms an amphipathic α-helix. These distinct features of the STIM2 K-rich domain cause an increased affinity for PI(4,5)P2, consistent with the lower activation threshold of STIM2 and a function as regulator of basal Ca2+ levels. Concomitant with higher affinity for PM lipids, binding of CaM (calmodulin) inhibited the interaction of the STIM2 K-rich domain with liposomes in a Ca2+ and PI(4,5)P2 concentration-dependent manner. Therefore we suggest that elevated cytosolic Ca2+ concentration down-regulates STIM2-mediated ER–PM contacts via CaM binding.

Cell Penetrating Mechanism of Bax Inhibiting Peptides.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4298-4298
Author(s):  
Jose A. Gomez ◽  
Tomoyuki Yoshida ◽  
Minh Lam ◽  
Clark W. Distelhorst ◽  
Shigemi Matsuyama
Keyword(s):  
Cell Death ◽  
Plasma Membrane ◽  
Fluorescent Dyes ◽  
Cultured Cells ◽  
Cell Penetrating Peptides ◽  
Dependent Manner ◽  
Cell Penetration ◽  
New Members ◽  
Cell Penetrating ◽  
High Degree

Abstract Plasma membrane is known to have a high degree of selectivity for molecular trafficking, and it does not allow the penetration of peptides larger than 3 amino acids. Previously known exceptions of large peptides that penetrate the plasma membrane are the Arginine rich peptides such as human immunodeficiency virus (HIV)-tat peptides. However, the mechanism of cell penetration of these peptides is largely unknown. Bax Inhibiting Peptides (BIP) are penta-peptides derived from the Bax binding domain of Ku70. At present, three types of BIP have been developed. Those are: VPMLK, VPTLK, and VPALR. All of these three BIPs directly bind Bax and inhibit Bax-mediated cell death in cultured cells as well as in animal study. Surprisingly, BIPs are cell permeable and autonomously enter the cytoplasm of the cells within 1 hr. Therefore BIPs are recognized as new members of cell penetration peptides. In this study, we investigated the mechanism of cell penetration of BIPs. DAMI cells (a human megakaryocyte cell line) and HeLa cells were used to investigate the detailed mechanism of cell penetration of BIPs. To detect the cell entry of BIPs, fluorescent dyes (fluorescein or tetramethylrodhamine) were conjugated to the N-terminus of BIPs and the cytoplasmic localization of BIPs was confirmed by confocal microscopy. Cell Penetration activities of BIPs were detected at 1 uM concentration in the culture medium. The significant accumulation of BIPs in the cytoplasm were detected within 1 hour of incubation both at 4 °C and 37 °C, suggesting that ATP-independent mechanism of cell penetration of BIP exists. However, cellular uptake of BIPs reaches plateau at 100 uM at 4 °C, whereas it increases in a dose dependent manner up to 1 mM at 37 °C without any sign of cytotoxicity. These results suggest that there are at least two mechanisms contributing to the cell penetration of BIPs that are, “ATP-independent (4 °C)” and “ATP-dependent (37 °C)” mechanisms. In addition to BIPs, we generated a series of mutated BIPs that do not bind Bax but retain cell-penetrating activities. We performed competition assay using fluorescence dye-labeled and non-labeled BIP (and the mutant BIPs), and the preliminary results suggest that there is a specific receptor for each peptide for its delivery into the cells. Our data also indicates that BIPs can deliver a cargo molecule (e.g. fluorescent dye) with at least the same molecular weight. Unlike other cell penetrating peptides, BIP has minimum toxicity due to its nature to inhibit Bax-mediated cell death. Along with the new data showing that BIP protects cells from pathological damages in cell culture and animal model, we will discuss the potential application of BIPs as a new type of drug delivery tool.

scholarly journals Domain architecture of the smooth-muscle plasma membrane: regulation by annexins

2005 ◽  
Vol 387 (2) ◽  
pp. 309-314 ◽  
Author(s):  
Annette DRAEGER ◽  
Susan WRAY ◽  
Eduard B. BABIYCHUK
Keyword(s):  
Smooth Muscle ◽  
Plasma Membrane ◽  
Membrane Lipids ◽  
Domain Architecture ◽  
Focal Adhesions ◽  
Membrane Lipid ◽  
Dependent Manner ◽  
Detailed Structural Analysis ◽  
Specific Subset ◽  
Associated Proteins

Individual signalling events are processed in distinct, spatially segregated domains of the plasma membrane. In a smooth muscle, the sarcolemma is divided into domains of focal adhesions alternating with caveolae-rich zones, both harbouring a specific subset of membrane-associated proteins. Recently, we have demonstrated that the sarcolemmal lipids are similarly segregated into domains of cholesterol-rich lipid rafts and glycerophospholipid-rich non-raft regions. In the present study, we provide a detailed structural analysis of the relationship between these proteinaceous and lipid domains. We demonstrate that the segregation of plasmalemmal protein constituents is intimately linked to that of the membrane lipids. Our results imply that lipid segregation is critical for the preservation of membrane protein architecture and essential for directional translocation of proteins to the sarcolemma. We show that the membrane lipid segregation is supported by the annexin protein family in a Ca2+-dependent manner. Eukaryotic cells harbour numerous, tissue-specific subsets of annexins. By examining the significance of this variety in a smooth muscle, we demonstrate that four different annexins target membrane sites of distinct lipid composition and that each annexin requires a different [Ca2+] for its translocation to the sarcolemma. Our results suggest that the interactions of annexins with distinct plasma membrane regions promote membrane segregation and, in combination with their individual Ca2+ sensitivity, might allow a spatially confined, graded response to a multitude of extra- or intracellular stimuli.

scholarly journals Defining how multiple lipid species interact with inward rectifier potassium (Kir2) channels

2020 ◽  
Vol 117 (14) ◽  
pp. 7803-7813 ◽  
Author(s):  
Anna L. Duncan ◽  
Robin A. Corey ◽  
Mark S. P. Sansom
Keyword(s):  
Plasma Membrane ◽  
Membrane Lipids ◽  
Membrane Lipid ◽  
Inward Rectifier ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Anionic Lipid ◽  
Lipid Interactions ◽  
Interaction Sites ◽  
Lipid Species

Protein–lipid interactions are a key element of the function of many integral membrane proteins. These potential interactions should be considered alongside the complexity and diversity of membrane lipid composition. Inward rectifier potassium channel (Kir) Kir2.2 has multiple interactions with plasma membrane lipids: Phosphatidylinositol (4, 5)-bisphosphate (PIP2) activates the channel; a secondary anionic lipid site has been identified, which augments the activation by PIP2; and cholesterol inhibits the channel. Molecular dynamics simulations are used to characterize in molecular detail the protein–lipid interactions of Kir2.2 in a model of the complex plasma membrane. Kir2.2 has been simulated with multiple, functionally important lipid species. From our simulations we show that PIP2interacts most tightly at the crystallographic interaction sites, outcompeting other lipid species at this site. Phosphatidylserine (PS) interacts at the previously identified secondary anionic lipid interaction site, in a PIP2concentration-dependent manner. There is interplay between these anionic lipids: PS interactions are diminished when PIP2is not present in the membrane, underlining the need to consider multiple lipid species when investigating protein–lipid interactions.

scholarly journals Ultrafast formation of domain walls of a charge density wave in SmTe3

2021 ◽  
Vol 103 (5) ◽  
Author(s):  
M. Trigo ◽  
P. Giraldo-Gallo ◽  
J. N. Clark ◽  
M. E. Kozina ◽  
T. Henighan ◽  
...  
Keyword(s):  
Charge Density ◽  
Charge Density Wave ◽  
Domain Walls ◽  
Density Wave ◽  
A Charge

Ultrafast switching to an insulating-like metastable state by amplitudon excitation of a charge density wave

2021 ◽  
Author(s):  
Naotaka Yoshikawa ◽  
Hiroki Suganuma ◽  
Hideki Matsuoka ◽  
Yuki Tanaka ◽  
Pierre Hemme ◽  
...  
Keyword(s):  
Charge Density ◽  
Metastable State ◽  
Charge Density Wave ◽  
Density Wave ◽  
Ultrafast Switching ◽  
A Charge

scholarly journals Ultrafast spot-profile LEED of a charge-density wave phase transition

2021 ◽  
Vol 118 (22) ◽  
pp. 221603
Author(s):  
G. Storeck ◽  
K. Rossnagel ◽  
C. Ropers
Keyword(s):  
Phase Transition ◽  
Charge Density ◽  
Charge Density Wave ◽  
Density Wave ◽  
Wave Phase ◽  
Charge Density Wave Phase ◽  
A Charge

scholarly journals Impact of Membrane Lipids on UapA and AzgA Transporter Subcellular Localization and Activity in Aspergillus nidulans

2021 ◽  
Vol 7 (7) ◽  
pp. 514
Author(s):  
Mariangela Dionysopoulou ◽  
George Diallinas
Keyword(s):  
Plasma Membrane ◽  
Subcellular Localization ◽  
Aspergillus Nidulans ◽  
Membrane Lipids ◽  
Membrane Lipid ◽  
Lipid Biosynthesis ◽  
Transport Kinetics ◽  
Negative Effect ◽  
And Function

Recent biochemical and biophysical evidence have established that membrane lipids, namely phospholipids, sphingolipids and sterols, are critical for the function of eukaryotic plasma membrane transporters. Here, we study the effect of selected membrane lipid biosynthesis mutations and of the ergosterol-related antifungal itraconazole on the subcellular localization, stability and transport kinetics of two well-studied purine transporters, UapA and AzgA, in Aspergillus nidulans. We show that genetic reduction in biosynthesis of ergosterol, sphingolipids or phosphoinositides arrest A. nidulans growth after germling formation, but solely blocks in early steps of ergosterol (Erg11) or sphingolipid (BasA) synthesis have a negative effect on plasma membrane (PM) localization and stability of transporters before growth arrest. Surprisingly, the fraction of UapA or AzgA that reaches the PM in lipid biosynthesis mutants is shown to conserve normal apparent transport kinetics. We further show that turnover of UapA, which is the transporter mostly sensitive to membrane lipid content modification, occurs during its trafficking and by enhanced endocytosis, and is partly dependent on autophagy and Hect-type HulARsp5 ubiquitination. Our results point out that the role of specific membrane lipids on transporter biogenesis and function in vivo is complex, combinatorial and transporter-dependent.

Sign in / Sign up

Export Citation Format

Share Document