The dynamic face of lipid membranes

Soft Matter ◽  
2021 ◽  
Author(s):  
Sudipta Gupta ◽  
Rana Ashkar

Lipid membranes envelope live cells and mediate vital biological functions through regulated spatiotemporal dynamics. This review highlights the role of neutron scattering, among other approaches, in uncovering the dynamic properties of lipid membranes.

2020 ◽  
Author(s):  
Bo Meng ◽  
Pedro P. Vallejo Ramirez ◽  
Katharina M. Scherer ◽  
Ezra Bruggeman ◽  
Julia C. Kenyon ◽  
...  

The scission of lipid membranes is a common biological process, often mediated by ESCRT complexes in concert with VPS4 assembling around the separation point. The functions of the ESCRT-I and ESCRT-III complexes are well established in certain of these cellular processes; however, the role of ESCRT-II remains contentious. Here, we devised a SNAP-tag fluorescent labelling strategy to understand the domain requirements of EAP45, the main component of ESCRT-II, in HIV egress, late endosome recruitment, and cytokinesis. We used TIRF microscopy to measure the spatial co-occurrence of the HIV structural polyprotein Gag with full length EAP45 in both fixed and live cells. Gag colocalises with the full length EAP45 comparably to ALIX, but this is lost on deletion of the EAP45 N terminus. Our findings reveal the H0 domain of the EAP45 protein is essential for linking to ESCRT-I during HIV budding and in anchoring at the late endosomal membrane, however in cytokinesis it is the Glue domain that is critical.


2016 ◽  
Author(s):  
◽  
Matthew McCune

This dissertation presents two research projects that apply theoretical and computational modeling to (1) describe and predict the formation and shape evolution of three-dimensional (3D) bioprinted tissue constructs, and (2) investigate the effect of a silica substrate on the structural and dynamic properties of a single fully hydrated lipid bilayer. (1) Bioprinting, a novel tissue engineering technique, has the ultimate goal of using 3D printers with bioink made from a person’s own cells to create tissues in the laboratory for transplantation or drug testing. The outcome of the post-bioprinting process, where the bioink particles fuse to form the desired 3D tissue construct, is difficult to predict and experimental techniques have generally been optimized through trial and error. To address this shortcoming, by employing theoretical modeling and computer simulations, we have developed and implemented an effective procedure that is capable of describing and predicting the shape dynamics during post-printing structure formation in 3D bioprinting. In particular, we have explained and demonstrated that the post-printing fusion process is considerably faster when using cylindrical instead of spheroidal bioink particles, a result that has considerable practical implication for extrusion bioprinting. (2) The study of lipid bilayers using neutron scattering experiments requires samples that contain a large stack of membranes. The analysis and computer simulation of such systems is challenging mainly due to the unknown amount of water separating the membranes. To overcome this difficulty, more recent experiments place single lipid membranes onto a support and stack about a hundred of them together. In this project we use molecular dynamics simulations of both free-standing and hydrated single-supported lipid bilayers to investigate the effect of the silica substrate on the structural and dynamical properties of the lipids and hydration waters. Our results may provide useful information in interpreting some recent neutron scattering experiments.


2021 ◽  
Vol 22 (16) ◽  
pp. 8461
Author(s):  
Emanuela Chiarella ◽  
Annamaria Aloisio ◽  
Stefania Scicchitano ◽  
Heather Mandy Bond ◽  
Maria Mesuraca

Powerful bioinformatics tools have provided a wealth of novel miRNA–transcription factor networks crucial in controlling gene regulation. In this review, we focus on the biological functions of miRNAs targeting ZNF521, explaining the molecular mechanisms by which the dysregulation of this axis contributes to malignancy. ZNF521 is a stem cell-associated co-transcription factor implicated in the regulation of hematopoietic, neural, and mesenchymal stem cells. The aberrant expression of ZNF521 transcripts, frequently associated with miRNA deregulation, has been detected in several tumors including pancreatic, hepatocellular, gastric, bladder transitional cell carcinomas as well as in breast and ovarian cancers. miRNA expression profiling tools are currently identifying a multitude of miRNAs, involved together with oncogenes and TFs in the regulation of oncogenesis, including ZNF521, which may be candidates for diagnostic and prognostic biomarkers of cancer.


2020 ◽  
Vol 11 (11) ◽  
Author(s):  
Chunliang Shang ◽  
Jie Qiao ◽  
Hongyan Guo

AbstractThe pre-metastatic niche is a favorable microenvironment for the colonization of metastatic tumor cells in specific distant organs. Lipid droplets (LDs, also known as lipid bodies or adiposomes) have increasingly been recognized as lipid-rich, functionally dynamic organelles within tumor cells, immune cells, and other stromal cells that are linked to diverse biological functions and human diseases. Moreover, in recent years, several studies have described the indispensable role of LDs in the development of pre-metastatic niches. This review discusses current evidence related to the biogenesis, composition, and functions of LDs related to the following characteristics of the pre-metastatic niche: immunosuppression, inflammation, angiogenesis/vascular permeability, lymphangiogenesis, organotropism, reprogramming. We also address the function of LDs in mediating pre-metastatic niche formation. The potential of LDs as markers and targets for novel antimetastatic therapies will be discussed.


2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Xiulin Jiang ◽  
Baiyang Liu ◽  
Zhi Nie ◽  
Lincan Duan ◽  
Qiuxia Xiong ◽  
...  

AbstractN6-methyladenosine (m6A) is the most prevalent, abundant and conserved internal cotranscriptional modification in eukaryotic RNAs, especially within higher eukaryotic cells. m6A modification is modified by the m6A methyltransferases, or writers, such as METTL3/14/16, RBM15/15B, ZC3H3, VIRMA, CBLL1, WTAP, and KIAA1429, and, removed by the demethylases, or erasers, including FTO and ALKBH5. It is recognized by m6A-binding proteins YTHDF1/2/3, YTHDC1/2 IGF2BP1/2/3 and HNRNPA2B1, also known as “readers”. Recent studies have shown that m6A RNA modification plays essential role in both physiological and pathological conditions, especially in the initiation and progression of different types of human cancers. In this review, we discuss how m6A RNA methylation influences both the physiological and pathological progressions of hematopoietic, central nervous and reproductive systems. We will mainly focus on recent progress in identifying the biological functions and the underlying molecular mechanisms of m6A RNA methylation, its regulators and downstream target genes, during cancer progression in above systems. We propose that m6A RNA methylation process offer potential targets for cancer therapy in the future.


Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1160
Author(s):  
F. Philipp Seib

Silk continues to amaze. This review unravels the most recent progress in silk science, spanning from fundamental insights to medical silks. Key advances in silk flow are examined, with specific reference to the role of metal ions in switching silk from a storage to a spinning state. Orthogonal thermoplastic silk molding is described, as is the transfer of silk flow principles for the triggering of flow-induced crystallization in other non-silk polymers. Other exciting new developments include silk-inspired liquid–liquid phase separation for non-canonical fiber formation and the creation of “silk organelles” in live cells. This review closes by examining the role of silk fabrics in fashioning facemasks in response to the SARS-CoV-2 pandemic.


2014 ◽  
Vol 106 (2) ◽  
pp. 224a
Author(s):  
Daeha Seo ◽  
Jiwook Kim ◽  
Justin Farlow ◽  
Hyunjung Lee ◽  
Paul Alivisatos ◽  
...  

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