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New Function For The Protein Bcl-xL: It Prevents Bone Breakdown

Date:
December 31, 2009
Source:
Journal of Clinical Investigation
Summary:
In blood cells, the protein Bcl-xL has a well-characterized role in preventing cell death by a process known as apoptosis. New research has now identified its functions in osteoclasts, cells that slowly breakdown bone (a process known as resorption). Surprisingly, not only does Bcl-xL prevent osteoclast apoptosis in mice, it also negatively regulates the bone-resorbing activity of osteoclasts.
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FULL STORY

In blood cells, the protein Bcl-xL has a well-characterized role in preventing cell death by a process known as apoptosis. However, its function(s) in osteoclasts, cells that slowly breakdown bone (a process known as resorption), has not been determined.

In addressing this issue, Sakae Tanaka and colleagues, at The University of Tokyo, Japan, have discovered that not only does Bcl-xL prevent osteoclast apoptosis in mice, it also negatively regulates the bone-resorbing activity of osteoclasts. They report their findings in the Journal of Clinical Investigation.

To determine the function of Bcl-xL in osteoclasts, the researchers generated mice lacking Bcl-xL only in osteoclasts. As in blood cells, Bcl-xL was shown to promote the survival of osteoclasts. Unexpectedly, however, the mutant mice exhibited marked osteopenia at one year of age. Further analysis indicated that the reduced bone mass was caused by increased osteoclast-mediated bone resorption and identified a potential underlying mechanism. Specifically, Bcl-xL was found to decrease the production of extracellular matrix proteins, which bind cell surface integrin molecules, leading to the activation of c-Src signaling pathways that are already known to promote osteoclast-mediated bone resorption.

Thus, in the absence of Bcl-xL, increased production of extracellular matrix proteins leads to increased osteoclast-mediated bone resorption.



Story Source:

The above story is based on materials provided by Journal of Clinical Investigation. Note: Materials may be edited for content and length.


Journal Reference:

  1. Iwasawa et al. The antiapoptotic protein Bcl-xL negatively regulates the bone-resorbing activity of osteoclasts in mice. Journal of Clinical Investigation, 2009; DOI: 10.1172/JCI39819

Cite This Page:

Journal of Clinical Investigation. "New Function For The Protein Bcl-xL: It Prevents Bone Breakdown." ScienceDaily. ScienceDaily, 31 December 2009. <www.sciencedaily.com/releases/2009/09/090914172339.htm>.
Journal of Clinical Investigation. (2009, December 31). New Function For The Protein Bcl-xL: It Prevents Bone Breakdown. ScienceDaily. Retrieved May 22, 2015 from www.sciencedaily.com/releases/2009/09/090914172339.htm
Journal of Clinical Investigation. "New Function For The Protein Bcl-xL: It Prevents Bone Breakdown." ScienceDaily. www.sciencedaily.com/releases/2009/09/090914172339.htm (accessed May 22, 2015).

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