Navigation Links
Ring-around-the-cell

Breaking down bone is a tough job. Yet, our bones undergo remodeling every day of our lives, as old material is cleared away so that new bone can form. In diseases such as osteoporosis, an imbalance in this process is responsible for the characteristic bone loss. New research at the Weizmann Institute of Science, which recently appeared in the online journal PLoS ONE, has revealed in unprecedented detail how the roving cells whose job is to digest bone seal off their work area as they get down to business.

The cells, called osteoclasts, have some unique features not seen in any other cell type. Osteoclasts move around the bone until they reach a site where they sense that their services are required, at which point they undergo a transformation called polarization. The polarized osteoclast sticks itself tightly to the bone, while an impermeable ring forms around the cell perimeter. This ring functions to keep the bone-eating acids and enzymes produced between the cell and the bone confined to the demolition site.

How does this ring form? To solve the mystery, Prof. Benjamin Geiger, Dean of Biology, and Prof. Lia Addadi of the Structural Biology Department, together with doctoral students Chen Luxenburg and Dafna Geblinger, and with the assistance of Dr. Eugenia Klein (electron microscopy unit) and Prof. Dorit Hanein and Karen Anderson of the Burnham Institute, San Diego, applied two different observation methods to samples of stripped-down, polarized osteoclasts: electron microscope imaging that allowed them to see fine details of the ring structure, and a light microscope method in which specific features glow. Because each method captures different information at a different scale, combining them was tricky, but the two together gave a much more extensive picture than either alone.

The researchers found that the ring is composed of dot-like structures called podosomes, which are anchored to the cell membrane. When the osteoclast is on the move, these little dots amble randomly around the cell, but when the cells prepare to dissolve the bone, they make a beeline for the edge. Scientists had been unsure how podosomes were involved in ring formation or, if they did form the ring, whether they somehow fused together or kept their individual shapes. The research team’s findings showed clearly that the ring is made of individual podosomes held together by interconnecting protein filaments they throw out to each other. "The podosomes are like folk dancers," says Geiger. "As soon as the music starts up, they join hands and form a tight circle. From afar, a circle of dancers looks like a blur, but now we have managed to make out the individual dancers."

Addadi points out that, from above, isolated podosomes look like a tent with rope-like lines radiating from a central pole. "In effect," she says, "the podosomes may be more than just seals. They appear to act as highly connected nodes of communication between the inside and outside of the cell, enabling the cell to adjust its activity according to the condition of the bone underneath."
'"/>

Source:American Committee for the Weizmann Institute of Science


Related biology news :

1. Growth in the sea comes down to a struggle for iron
2. Estrogen-like Component of Plastic Stimulates Growth of Certain Prostate Cancer Cells
3. Growth in biomass could put US on road to energy independence
4. Embryonic Stem Cells Treated With Growth Factor Reverse Hemophilia In Mice: UNC Researchers
5. Missing Receptor Molecule Causes Tumor Growth
6. Growth hormone is made in the brain, report scientists
7. Growth factor-promoting angiogenesis expressed in tumor cells and normal neurons
8. New Research Shows Artificial Light at Night Stimulates Breast Cancer Growth in Laboratory Mice
9. Growth factor stimulates rapid extension of key motor neurons in brain
10. Growth hormone is not the anti-aging bullet for healthy adults
11. Female sex hormones play a vital role in defense against sexually transmitted diseases

Post Your Comments:
*Name:
*Comment:
*Email:


(Date:3/20/2017)... At this year,s CeBIT Chancellor Dr. Angela Merkel visited ... to the DERMALOG stand together with the Japanese Prime Minster Shinzo Abe. ... the largest German biometrics company the two government leaders could see the ... well as DERMALOG´s multi-biometrics system.   Continue Reading ... ...
(Date:3/13/2017)... HAMBURG, Germany , March 13, 2017 Future of ... ... DERMALOGs Face Matching enables to match ... characteristics forms the basis to identify individuals. (PRNewsFoto/Dermalog Identification Systems) ... DERMALOG,s "Face Matching" is the fastest software for ...
(Date:3/7/2017)... -- Brandwatch , the leading social intelligence company, today announces ... to uncover insights to support its reporting, help direct future campaigns, ... leading youth charity will be using Brandwatch Analytics social listening and ... understanding of the topics and issues that are a priority for ... "Until ...
Breaking Biology News(10 mins):
(Date:3/27/2017)... DUBLIN , March 27, 2017 ... access to a comprehensive library of reports on Valero ... the transportation fuels and petrochemical industries. ...      (Logo: http://photos.prnewswire.com/prnh/20160330/349511LOGO) ... is biofuel production to go green. Ethanol today, even though ...
(Date:3/27/2017)... , March 27, 2017  Trovagene, Inc. (NASDAQ: TROV), ... Chief Executive Officer, Bill Welch , will be ... 2017 at 9:00 AM EDT at the Essex House ... Welch, and Chief Scientific Officer, Mark Erlander , ... during the conference.   The presentation will be ...
(Date:3/24/2017)... , March 24, 2017 MiMedx Group, Inc. ... utilizing human placental tissue allografts and patent-protected processes to ... sectors of healthcare, announced today  that it will present ... York , NY.  Parker H. "Pete" Petit, Chairman ... Officer, Christopher M. Cashman , EVP and Chief ...
(Date:3/24/2017)... Ltd. ("Sinovac" or the "Company") (NASDAQ: SVA), a leading provider of ... its board of directors has amended its shareholder rights plan. The amendment ... to March 27, 2018. The amendment was not in response to any ... ... is a China -based biopharmaceutical company that focuses ...
Breaking Biology Technology: