scholarly journals Amphiphilic Peptides with Flexible Chains for Tuning Supramolecular Morphologies, Macroscopic Properties and Biological Functions

2021 ◽  
Vol 79 (11) ◽  
pp. 1033-1040
Author(s):  
Takahiro Muraoka
2015 ◽  
Vol 57 ◽  
pp. 177-187 ◽  
Author(s):  
Jennifer N. Byrum ◽  
William Rodgers

Since the inception of the fluid mosaic model, cell membranes have come to be recognized as heterogeneous structures composed of discrete protein and lipid domains of various dimensions and biological functions. The structural and biological properties of membrane domains are represented by CDM (cholesterol-dependent membrane) domains, frequently referred to as membrane ‘rafts’. Biological functions attributed to CDMs include signal transduction. In T-cells, CDMs function in the regulation of the Src family kinase Lck (p56lck) by sequestering Lck from its activator CD45. Despite evidence of discrete CDM domains with specific functions, the mechanism by which they form and are maintained within a fluid and dynamic lipid bilayer is not completely understood. In the present chapter, we discuss recent advances showing that the actomyosin cytoskeleton has an integral role in the formation of CDM domains. Using Lck as a model, we also discuss recent findings regarding cytoskeleton-dependent CDM domain functions in protein regulation.


1994 ◽  
Vol 72 (04) ◽  
pp. 578-581 ◽  
Author(s):  
T McNally ◽  
S E Cotterell ◽  
I J Mackie ◽  
D A Isenberg ◽  
S J Machin

Summaryβ2 glycoprotein-I (β2GPI), a cofactor for antiphospholipid antibody (aPA) binding, binds to many anionic macromolecules including heparin. The nature of this interaction with heparin is not well understood and its effect on the purported biological functions of β2GPI is unknown.We have examined the interactions of dermatan sulphate (DS) and different pharmaceutical preparations of heparin with β2GPI by crossed immunoelectrophoresis (CIE) and investigated the effect of these agents on plasma levels of p2GPI antigen (β2GPI: Ag) by a standardised enzyme linked immunosorbent assay (ELISA). P2GPI aPA cofactor activity (β2GPI:Cof) was also measured using a modified solid phase an-ti-phosphatidylserine (aPS) ELISA. CIE results confirmed a heparin-β2GPI interaction with unfractionated (UF) heparin. β2GPI:Ag levels were unaffected by any of the preparations investigated. There were no significant differences in β2GPI:Cof activities of the samples containing LMW heparins or DS but levels of β2GPI:Cof were increased in samples containing UF sodium and calcium heparin preparations (0.5 IU/ml Monoparin, p <0.05, and 10 IU/ml Liquemin and Calcipa-rine, p <0.05).


2019 ◽  
Author(s):  
Zacharias Thiel ◽  
Pablo Rivera-Fuentes

Many biomacromolecules are known to cluster in microdomains with specific subcellular localization. In the case of enzymes, this clustering greatly defines their biological functions. Nitroreductases are enzymes capable of reducing nitro groups to amines and play a role in detoxification and pro-drug activation. Although nitroreductase activity has been detected in mammalian cells, the subcellular localization of this activity remains incompletely characterized. Here, we report a fluorescent probe that enables super-resolved imaging of pools of nitroreductase activity within mitochondria. This probe is activated sequentially by nitroreductases and light to give a photo-crosslinked adduct of active enzymes. In combination with a general photoactivatable marker of mitochondria, we performed two-color, threedimensional, single-molecule localization microscopy. These experiments allowed us to image the sub-mitochondrial organization of microdomains of nitroreductase activity.<br>


2019 ◽  
Author(s):  
Zacharias Thiel ◽  
Pablo Rivera-Fuentes

Many biomacromolecules are known to cluster in microdomains with specific subcellular localization. In the case of enzymes, this clustering greatly defines their biological functions. Nitroreductases are enzymes capable of reducing nitro groups to amines and play a role in detoxification and pro-drug activation. Although nitroreductase activity has been detected in mammalian cells, the subcellular localization of this activity remains incompletely characterized. Here, we report a fluorescent probe that enables super-resolved imaging of pools of nitroreductase activity within mitochondria. This probe is activated sequentially by nitroreductases and light to give a photo-crosslinked adduct of active enzymes. In combination with a general photoactivatable marker of mitochondria, we performed two-color, threedimensional, single-molecule localization microscopy. These experiments allowed us to image the sub-mitochondrial organization of microdomains of nitroreductase activity.<br>


2013 ◽  
Vol 35 (10) ◽  
pp. 1179-1188 ◽  
Author(s):  
Hong WANG ◽  
Gang-Bo LI ◽  
Da-Yong ZHANG ◽  
Jing LIN ◽  
Bao-Long SHENG ◽  
...  

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