Navigation Links
Degrading proteins to divide cells
Date:8/26/2011

From bacteria to humans, all forms of life are based on the capacity of one cell to divide into two or more identical daughter cells. In doing so, cells have to produce a copy of their genetic material (DNA) and separate it into two identical sets, one for each daughter cell. Immediately after duplication and before its segregation, DNA is packed in chromosomes that consist of two identical strands joined at a point along their length, called centromeres. Centromeres ensure accurate separation of the chromosomes between daughter cells by directing the assembly of the molecular scaffolding that helps separate cells. The group of scientists led by the IBMB-CSIC Professor and IRB Barcelona researcher Ferran Azorn has identified the main instrument that Drosophila cells use to control the levels of the CenH3 protein, a key element for defining the identity and function of the centromere in the fruit fly.

CenH3 is a unique variant of conventional histones proteins responsible for DNA packaging found exclusively in the centromeres of all eukaryotes studied to date. "The presence of CenH3 in chromosome regions other than the centromere is sufficient to cause defects in chromosome separation in Drosophila and in budding yeast", explains Azorn. In yeast and Drosophila, the controlled degradation of CenH3 is known to be one of the mechanisms that regulate its location in the centromere. How this mechanism works, however, has been a mystery until now. The study, led by Azorn and published online on August 25 in Current Biology, shows that CenH3 interacts specifically with the protein partner of pair (Ppa), involved in directing proteins toward degradation. "We have demonstrated that degradation of CenH3 is essential for limiting its presence at the centromeres and that this degradation is mediated by the protein Ppa, which targets CenH3 to one of the cell's degradation mechanisms, the proteasome", explains Azorn. The proteasome is a barrel-shape protein structure that breaks down and disposes of unfunctional or unnecessary proteins in the cell. When a protein has to be degraded it needs to be somehow 'tagged' for degradation so it can be detected efficiently and directed to the proteasome. Ppa is part of a 'degradation labelling complex' that marks proteins such as CenH3 with a molecule called ubiquitin for destruction in the proteasome.

"The split between insects and humans during evolution must have occurred about 5 hundred millions years ago. However, most of the molecular components of the centromere have remained practically unchanged in all eukaryotic organisms: CenH3, for example is found in all eukaryotic centromeres", says Azorn. In Drosophila and also in humans impairment of chromosome segregation during cell division may contribute to disease and birth defects. Thus, errors in centromere function can lead to chromosome instability and aberrant cell division, both of which are often observed in cancer cells. Given the essential roles of the centromeric CenH3 during cell division and the similarities in centromeric structure and function observed among all eukaryotes, the insights into Drosophila centromere stability provided by Azorn's group may contribute to our understanding of the genetic basis of cancer.


'/>"/>

Contact: Itziar Castanedo
itziar.castanedo@irbbarcelona.org
34-934-031-301
Institute for Research in Biomedicine (IRB Barcelona)
Source:Eurekalert

Related biology news :

1. A quarter of the worlds population depends on degrading land
2. Rots unique wood degrading machinery to be harnessed for better biofuels production
3. Three-part handoff delivers proteins to membrane surface
4. Newfound hijacked proteins linked to salmonella virulence
5. Improved method for capturing proteins holds promise for biomedical research
6. Good prion-like proteins boost immune response, UT Southwestern scientists report
7. Caltech researchers increase the potency of HIV-battling proteins
8. Bacterial attack strategy uses special delivery of toxic proteins
9. A chaperone system guides tail-anchored membrane proteins to their destined membrane
10. New tasks attributed to Aurora proteins in cell division
11. Penn researchers help nanoscale engineers choose self-assembling proteins
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:5/6/2017)... -- RAM Group , Singaporean based technology ... biometric authentication based on a novel  quantum-state ... perform biometric authentication. These new sensors are based on a ... Group and its partners. This sensor will have widespread ... security. Ram Group is a next generation sensor ...
(Date:4/19/2017)... 2017 The global military biometrics ... marked by the presence of several large global players. ... five major players - 3M Cogent, NEC Corporation, M2SYS ... nearly 61% of the global military biometric market in ... global military biometrics market boast global presence, which has ...
(Date:4/17/2017)... April 17, 2017 NXT-ID, Inc. (NASDAQ: ... the filing of its 2016 Annual Report on Form 10-K on ... ... is available in the Investor Relations section of the Company,s website ... SEC,s website at http://www.sec.gov . 2016 Year Highlights: ...
Breaking Biology News(10 mins):
(Date:10/10/2017)... ... October 10, 2017 , ... USDM Life ... for the life sciences and healthcare industries, announces a presentation by Subbu Viswanathan ... The presentation, “Automating GxP Validation for Agile Cloud Platforms,” will present a revolutionary ...
(Date:10/9/2017)... , Oct. 9, 2017  BioTech Holdings ... mechanism by which its ProCell stem cell therapy ... limb ischemia.  The Company, demonstrated that treatment with ... of limbs saved as compared to standard bone ... molecule HGF resulted in reduction of therapeutic effect.  ...
(Date:10/9/2017)... ... 09, 2017 , ... At its national board meeting in North Carolina, ... University’s Departments of Physics and Astronomy, has been selected for membership in ARCS ... for the 2015 Breakthrough Prize in Fundamental physics for the discovery of the accelerating ...
(Date:10/9/2017)... ... October 09, 2017 , ... ... medical journal, Epilepsia, Brain Sentinel’s SPEAC® System which uses the surface electromyography ... generalized tonic-clonic seizures (GTCS) using surface electromyography (sEMG). The prospective multicenter phase ...
Breaking Biology Technology: