Nav: Home

Adhesion ABC

January 05, 2016

Scientists from the Mechanobiology Institute, Singapore (MBI) at the National University of Singapore have discovered the universal building blocks that cells use to form initial connections with the surrounding environment. These early adhesions have a consistent size of 100 nanometres, are made up of a cluster of around 50 integrin proteins and are the same even when the surrounding surface is hard or soft. Deciphering the universal nature of adhesion formation may reveal how tumour cells sense and migrate on surfaces of different rigidity, which is a hallmark of metastasis, the devastating ability of cancer to spread throughout the body. This study was published in the 7 December 2015 issue of Developmental Cell.

Building blocks for cell adhesion

Cells interact with their environment through protein complexes called focal adhesions. These act as the hands and feet of the cell, and allow it to form physical connections with the surrounding surface, enabling the sending and receiving of mechanical signals from the environment. This, in turn, drives many of the cell's decisions, such as determining what type of cell to develop into, or where in the body it should move to. However, within the body there are a variety of different surfaces that cells can grow on, from soft surfaces such as brain matter to hard surfaces like bone. Although cells can form focal adhesions on both soft and hard surfaces, how they assemble on surfaces of such different rigidity is still a mystery.

The major protein in the focal adhesion complex is integrin, which spans the cell membrane, forming a link between the internal skeleton of the cell and external surface. Integrin binds to a sequence of three amino acids (arginine-glycine-aspartic acid, also known as RGD). By growing cells on either hard glass or fluid artificial membranes coated with RGD, and observing adhesion formation with super-resolution microscopy, a team of MBI scientists led by Dr Rishita Changede and Professor Michael Sheetz was able to investigate the molecular origins of adhesion formation on surfaces of different rigidity. Analysing this data with custom-built computational algorithms allowed them to accurately measure adhesion size, and even count the number of integrins in each adhesion.

Remarkably, they discovered that cells growing on soft or hard surfaces form adhesions in the exact same way. These early, or nascent, adhesions assemble from clusters of approximately 50 integrins and have a diameter of around 100 nanometres. Despite the small size of early adhesions compared to the average cell surface area of 3,500 square micrometres, they enable the cell to form an initial attachment to the environment. Intriguingly, altering the density of the RGD coating also had no effect on the formation of early adhesions. The same integrin clusters were formed, with a consistent protein composition and size, even when the RGD density was reduced 10-fold.

As the early adhesions formed independently of surface rigidity or RGD density, they represent universal, modular units for cell adhesion to the environment. Similar to building blocks, these modular units could aggregate together to form larger adhesions. Formation of early adhesions was also assisted by rapid recruitment of the mechanosensor protein, talin. Once the cell forms these early adhesions on soft or hard surfaces, it can use talin and other mechanosensitive proteins to develop force. Depending on the force received from the surface, the early adhesions can either recycle back into the cell, or mature into focal adhesions.

This study reveals that cells form early adhesions from integrin clusters as a first response to their environment, and that these universal, modular units of adhesion assemble without the need for external stimuli from the surrounding surface. Understanding how these universal early adhesions form the building blocks for mature focal adhesions will provide new insights into focal adhesion mediated mechanosignalling and its vital role in cell growth, development, and disease.
-end-


National University of Singapore

Related Environment Articles:

How atrazine regulations have influenced the environment
Opposing chemical trends linked to atrazine regulations from 1990s.
COVID-19 and the built environment
Social distancing has Americans mostly out of the places they usually gather and in their homes as we try to reduce the spread of COVID-19.
A broad look at plant-environment interactions
Three plant science journals---the American Journal of Botany (AJB), Applications in Plant Sciences (APPS), and the International Journal of Plant Sciences (IJPS)---have joined efforts to provide a broad look at how plants interact with their environment.
Observing proteins in their natural environment
Certain medications, such as those used to treat cancer, lose their effect because proteins in the membrane of the target cell simply expel them again.
New research looks at type 1 diabetes and changes in the environment
Studies have shown a rapid increase in new cases of type 1 diabetes worldwide.
Chemicals in the environment: A focus on mixtures
The real world is marked by multiple stressors, among them cocktails of chemicals.
Rubber in the environment
The tread on the tyre is worn out, new tyres are needed.
How we care for the environment may have social consequences
Anyone can express their commitment to the environment through individual efforts, but some pro-environmental or 'green' behaviors may be seen as either feminine or masculine, which Penn State researchers say may have social consequences.
Neighborhood environment and health
It is well understood that urban black males are at a disproportionately high risk of poor health outcomes.
Children shape their learning environment
A close collaboration between University of Connecticut and Interacting Minds at Aarhus University researchers is exploring how parents and children influence each other when they interact, and the longer term impact this has on language acquisition.
More Environment News and Environment Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.