scholarly journals Molecular Force Sensors: From Fundamental Concepts toward Applications in Cell Biology

2016 ◽  
Vol 4 (1) ◽  
pp. 1600441 ◽  
Author(s):  
Melis Goktas ◽  
Kerstin G. Blank
2018 ◽  
Author(s):  
Y. Murad ◽  
I. T.S. Li

AbstractTo understand the mechanical forces involved in cell adhesion, molecular force sensors have been developed to study tension through adhesion proteins. Recently, a class of molecular force sensors called tension gauge tether (TGT) have been developed that rely on irreversible force-dependent dissociation of DNA duplex to study cell adhesion forces. While the TGT offer high signal-to-noise ratio and is ideal for studying fast / single molecular adhesion processes, quantitative interpretation of experimental results has been challenging. Here we used computational approach to investigate how TGT fluorescence readout can be quantitatively interpreted. In particular we studied force sensors made of a single TGT, multiplexed single TGTs, and two TGTs connected in series. Our results showed that fluorescence readout using a single TGT can result from drastically different combinations of force history and adhesion event density that span orders of magnitude. In addition, the apparent behaviour of the TGT is influenced by the tethered receptor-ligand, making it necessary to calibrate the TGT with every new receptor-ligand. To solve this problem, we proposed a system of two serially connected TGTs. Our result shows that not only is the ratiometric readout of serial TGT independent of the choice of receptor-ligand, it is able to reconstruct force history with sub-pN force resolution. This is also not possible by simply multiplexing different types of TGTs together. Lastly, we systematically investigated how sequence composition of the two serially connected TGTs can be tuned to achieve different dynamic range. This computational study demonstrated how serially connected irreversible molecular dissociation processes can accurately quantify molecular force, and laid the foundation for subsequent experimental studies.


2020 ◽  
Vol 48 (1) ◽  
pp. 1-16 ◽  
Author(s):  
Susana M. Beltrán ◽  
Marvin J. Slepian ◽  
Rebecca E. Taylor

2017 ◽  
Vol 50 (23) ◽  
pp. 233001 ◽  
Author(s):  
Meenakshi Prabhune ◽  
Florian Rehfeldt ◽  
Christoph F Schmidt

2021 ◽  
Author(s):  
M. Sergides ◽  
L. Perego ◽  
T. Galgani ◽  
C. Arbore ◽  
F.S. Pavone ◽  
...  

AbstractCells sense mechanical signals and forces to probe the external environment and adapt to tissue morphogenesis, external mechanical stresses, and a wide range of diverse mechanical cues. Here, we propose a combination of optical tools to manipulate single cells and measure the propagation of mechanical and biochemical signals inside them. Optical tweezers are used to trap microbeads that are used as handles to manipulate the cell plasma membrane; genetically encoded FRET-based force sensors inserted in F-actin and alpha-actinin are used to measure the propagation of mechanical signals to the cell cytoskeleton; while fluorescence microscopy with single molecule sensitivity can be used with a huge array of biochemical and genetic sensors. We describe the details of the setup implementation, the calibration of the basic components and preliminary characterization of actin and alpha-actinin FRET-based force sensors.


2022 ◽  
Author(s):  
Rachel L. Bender ◽  
Khalid Salaita

2021 ◽  
Vol 136 (3) ◽  
Author(s):  
M. Sergides ◽  
L. Perego ◽  
T. Galgani ◽  
C. Arbore ◽  
F. S. Pavone ◽  
...  

AbstractCells sense mechanical signals and forces to probe the external environment and adapt to tissue morphogenesis, external mechanical stresses and a wide range of diverse mechanical cues. Here, we propose a combination of optical tools to manipulate single cells and measure the propagation of mechanical and biochemical signals inside them. Optical tweezers are used to trap microbeads that are used as handles to manipulate the cell plasma membrane; genetically encoded FRET-based force sensors inserted in F-actin and alpha-actinin are used to measure the propagation of mechanical signals to the cell cytoskeleton, while fluorescence microscopy with single-molecule sensitivity can be used with a huge array of biochemical and genetic sensors. We describe the details of the setup implementation, the calibration of the basic components and preliminary characterization of actin and alpha-actinin FRET-based force sensors.


Author(s):  
William H. Zucker

Planktonic foraminifera are widely-distributed and abundant zooplankters. They are significant as water mass indicators and provide evidence of paleotemperatures and events which occurred during Pleistocene glaciation. In spite of their ecological and paleological significance, little is known of their cell biology. There are few cytological studies of these organisms at the light microscope level and some recent reports of their ultrastructure.Specimens of Globigerinoides ruber, Globigerina bulloides, Globigerinoides conglobatus and Globigerinita glutinata were collected in Bermuda waters and fixed in a cold cacodylate-buffered 6% glutaraldehyde solution for two hours. They were then rinsed, post-fixed in Palade's fluid, rinsed again and stained with uranyl acetate. This was followed by graded ethanol dehydration, during which they were identified and picked clean of debris. The specimens were finally embedded in Epon 812 by placing each organism in a separate BEEM capsule. After sectioning with a diamond knife, stained sections were viewed in a Philips 200 electron microscope.


Author(s):  
W. Bernard

In comparison to many other fields of ultrastructural research in Cell Biology, the successful exploration of genes and gene activity with the electron microscope in higher organisms is a late conquest. Nucleic acid molecules of Prokaryotes could be successfully visualized already since the early sixties, thanks to the Kleinschmidt spreading technique - and much basic information was obtained concerning the shape, length, molecular weight of viral, mitochondrial and chloroplast nucleic acid. Later, additonal methods revealed denaturation profiles, distinction between single and double strandedness and the use of heteroduplexes-led to gene mapping of relatively simple systems carried out in close connection with other methods of molecular genetics.


Author(s):  
K. Jacobson ◽  
A. Ishihara ◽  
B. Holifield ◽  
F. Zhang

Our laboratory is concerned with understanding the dynamic structure of the plasma membrane with particular reference to the movement of membrane constituents during cell locomotion. In addition to the standard tools of molecular cell biology, we employ both fluorescence recovery after photo- bleaching (FRAP) and digitized fluorescence microscopy (DFM) to investigate individual cells. FRAP allows the measurement of translational mobility of membrane and cytoplasmic molecules in small regions of single, living cells. DFM is really a new form of light microscopy in that the distribution of individual classes of ions, molecules, and macromolecules can be followed in single, living cells. By employing fluorescent antibodies to defined antigens or fluorescent analogs of cellular constituents as well as ultrasensitive, electronic image detectors and video image averaging to improve signal to noise, fluorescent images of living cells can be acquired over an extended period without significant fading and loss of cell viability.


Author(s):  
A. Hakam ◽  
J.T. Gau ◽  
M.L. Grove ◽  
B.A. Evans ◽  
M. Shuman ◽  
...  

Prostate adenocarcinoma is the most common malignant tumor of men in the United States and is the third leading cause of death in men. Despite attempts at early detection, there will be 244,000 new cases and 44,000 deaths from the disease in the United States in 1995. Therapeutic progress against this disease is hindered by an incomplete understanding of prostate epithelial cell biology, the availability of human tissues for in vitro experimentation, slow dissemination of information between prostate cancer research teams and the increasing pressure to “ stretch” research dollars at the same time staff reductions are occurring.To meet these challenges, we have used the correlative microscopy (CM) and client/server (C/S) computing to increase productivity while decreasing costs. Critical elements of our program are as follows:1) Establishing the Western Pennsylvania Genitourinary (GU) Tissue Bank which includes >100 prostates from patients with prostate adenocarcinoma as well as >20 normal prostates from transplant organ donors.


Sign in / Sign up

Export Citation Format

Share Document