BioEssays Review on Mitotic Phosphatase Specificity now Online

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Great News, our review on how phosphatase specificity is controlled during mitosis has been re-published in BioEssays and is now Online!

This review was originally published in Inside the Cell, which unfortunately has shut down.

But the good news is that it is still Open Access, so that means its free for everyone to read! And is now also indexed in PubMed

During mitotic exit, phosphatases reverse thousands of phosphorylation events in a specific temporal order to ensure that cell division occurs correctly. This review explores how the physicochemical properties of the phosphosite and surrounding amino acids affect interactions with phosphatase/s and help determine the dephosphorylation of individual phosphorylation sites during mitotic exit.

The Full-text download for the Article can be found here [Link]

Citation: Rogers, S. et al. (2016) Mechanisms regulating phosphatase specificity and the removal of individual phosphorylation sites during mitotic exit. BioEssays, 38, S24–S32.

 

Save the Date: ACCM2017 – March 27-29th – “Cell Cycle, DNA Damage Response & Telomeres”

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The Australian Cell Cycle Community

2017 Flyer v2-01

The 16th Australian Cell Cycle Meeting: “Cell Cycle, DNA Damage Response & Telomeres” will be held from Monday the 27th to Wednesday the 29th of March, 2017 at the Powerhouse Museum, in Sydney Australia.

The 2017 meeting will be the largest ever ACCM meeting, bringing together the fields of Cell Cycle, DNA Damage Response, and Telomere biology into one amazing meeting.

We are also very excited to announce 4x Plenary Lectures for #ACCM2017:

  • Julia P. Cooper
    Telomere Biology Center for Cancer Research (NCI) Bethesda, MD, USA
  • Daniel Durocher
    DNA Damage The Lunenfeld-Tanenbaum Research Institute Toronto, Ontario Canada
  • Marcos Malumbres
    Cell Division & Cancer National Cancer Research Centre (CNIO) Madrid, Spain
  • Antoine van Oijen
    Single-molecule biophysics, DNA replication Head School of Chemistry, University of Wollongong NSW, Australia
Registration for the ACCM2017 will open in October 2016, and more details, including a fantastic line up of National speakers will be announced…

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Post-doctoral positions available in the CMRI Genome Integrity Group (Cesare Laboratory)

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The Australian Cell Cycle Community

Dr Cesare’s laboratory has postdoctoral positions, fully funded for three years, starting in late 2016 or early 2017.  We are in search of exceptional young scientists, interested in pursuing research on telomeres and genome stability. Opportunities exist in my lab for post-doctoral scientists to investigate:

1)      the interplay between genomic DNA replication stress, or DNA damage, and telomere deprotection

2)      mechanisms of telomere deprotection during ageing and in cancer

3)      telomere biology in mitosis

4)      mitotic chromosome dynamics

5)      post-translational modifications in telomere deprotection signalling

6)      nuclear architecture in the DNA damage response

Ideal candidates will be hard working, independent, and creative in their experimental approach. I also welcome candidates with established excellence in CRISPR/Cas9 mediated gene-editing, quantitative microscopy and/or automated imaging analysis, super-resolution microscopy, proteomics, ChIP-seq and RNA-seq.

Dr Cesare’s is located at the Children’s Medical Research Institute (CMRI) in Sydney, Australia. CMRI is home to the highest concentration of telomere research labs at a…

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Switching off Cancers Diversity

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JCS paper

A defining feature in over 2/3rds of all solid tumours is the continual loss and gain of whole are small parts of chromosomes. This instability, or CIN for short, strongly implicated in tumour initiation, progression, chemoresistance and poor prognosis. CIN is created through failures during mitosis, whereby whole or parts of a chromosome are segregated incorrectly, thereby created daughter cells with unequal chromosome numbers. Consequently, understanding how mitosis is regulated is essential for uncovering the mechanisms allowing CIN to arise and drive cancer. In our recent publication, we discovered the mechanisms controlling the key regulatory pathway critical to ensuring cells exit mitosis correctly. At the centre of this pathway is a gene call MASTL (short for ‘Microtubule Associated Serine/Threonine Kinase-Like’). The primary function of MASTL is to ensure that the cellular breaks (the phosphatase PP2A), is turned off during mitosis so that the accelerator (Cdk1 kinase) can drive the cell into mitosis. Much like a car, having the accelerator and breaks on at the same time is a bad idea, unless you like the smell of burning rubber. To successfully exit mitosis, and to perfectly segregate chromosomes, the cell must take the foot off the accelerator and turn on the breaks. Because MASTL is the central regulator ensuring the breaks are coordinated with the accelerator, it is essential to understand how MASTL is controlled. To this end, we uncovered that MASTL must be rapidly turned off to allow cells to exit mitosis, and this inactivation is carried out by another cellular brake call PP1 phosphatase (Rogers et al, JCS 2016). Now that we have identified and mapped this novel mitotic exit switch, we hope to be able to shed new light on how CIN drives the initiation and evolution cancer. We believe that with further study we will be able to better predict patient response to chemotherapy, and also identify new ways to ‘switch off’ highly unstable tumours, thereby improving treatment for patients that currently have a very poor prognosis.

Image of Interphase HeLa cell stained for Actin (red), DNA (blue) and the co-localisation of MASTL and PP1 by Proximity Ligation Assay (PLA; green).
Credit: Sam Rogers and Cell Division Lab

 

New Publication: Clinical Overview of MDM2/X-Targeted Therapies

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Great news, we have a new Mini-Review published in Frontiers Oncology entitled “Clinical Overview of MDM2/X-Targeted Therapies“, which is apart of the Research Topic Human tumor-derived p53 mutants: a growing family of oncoproteins

Here is a little snippet from the Abstract to wet your appetite!

MDM2 and MDMX are the primary negative regulators of p53, which under normal conditions maintain low intracellular levels of p53 by targeting it to the proteasome for rapid degradation and inhibiting its transcriptional activity. Both MDM2 and MDMX function as powerful oncogenes and are commonly over-expressed in some cancers, including sarcoma (~20%) and breast cancer (~15%).

In this overview, we will review the current MDM2- and MDMX-targeted therapies in development, focusing particularly on compounds that have entered into early phase clinical trials. We will highlight the challenges pertaining to predictive biomarkers for and toxicities associated with these compounds, as well as identify potential combinatorial strategies to enhance its anti-cancer efficacy.

The article is Open Access, which means its free for everyone and anyone to read and download!

You can view and download it directly here [Link]

The Early-Mid Career Funding Crisis in Australian Research

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Its no secrete that Funding for Science in Australia, and around the world (see refs below), is in decline. The result is lower and lower success rates. While we wait for the #NHMRC to release the outcomes for 2015, the word on the street is that we can expect only 10-12% of grants to be successful. In other words, for 90% of Australia’s researchers they are wasting ~3 months of the year for nothing. Consequently as the funding pool decreases, funds naturally flow towards ‘sure bet’ senior researchers. This means that this wasted time is felt the hardest by early- and mid- career researchers (#EMCRs) who cannot compete with the long CVs of their senior peers, and are seen as a potential risky investment. Below is a graph I put together from the 2013 data, which is the most up to date information currently at hand. This trend of funding more senior researchers is clearly seen in the massive increase in average age of the CIA (chief investigator) on project grants over the past 30 years. It used to peak around 40 years, which perfectly aligned with the drop off in fellowships. So there was a very clear and clean transition from Post-Doctoral Funding for those that wanted to transition to a team leader role. However now, the average age has shifted to >50 years. This has created a significant 10-15 year ‘Funding Hole’ for EMCRs, where there are very limited number of fellowships on offer, and little to no chance of securing a project grant. While there has been a lot of talk about this black box, no solution or action has been taken to stem the loss of young, bright and talented researchers being forced out of research. Without action soon, we run the real risk that there will be no succession plan, and Australia’s ability to remain internationally competitive will be set back decades.

 

2013 NHMRC Data

 

Funding issues in the US system:
1. Alberts, B., Kirschner, M. W., Tilghman, S. & Varmus, H. Rescuing US biomedical research from its systemic flaws. PNAS 111, 5773–5777 (2014).
2. Cyranoski, D., Gilbert, N., Ledford, H., Nayar, A. & Yahia, M. Education: The PhD factory. Nature 472, 276–279 (2011).
3. Committee to Review the State of Postdoctoral Experience in Scientists and Engineers et al. The Postdoctoral Experience Revisited. (National Academies Press (US), 2014).
4. Powell, K. The future of the postdoc. Nature 520, 144–147 (2015).
5. Alberts, B., Kirschner, M. W., Tilghman, S. & Varmus, H. Opinion: Addressing systemic problems in the biomedical research enterprise. Proc. Natl. Acad. Sci. U.S.A. 112, 1912–1913 (2015).

 

AntiOxidants and Cancer: A complicated story

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A recent high profile publication in Science Translational Medicine proposed that antioxidants might increase the rate of metastasis in mice models of melanoma.

NAC and the soluble vitamin E analog Trolox markedly increased the migration and invasive properties of human malignant melanoma cells but did not affect their proliferation. Both antioxidants increased the ratio between reduced and oxidized glutathione in melanoma cells and in lymph node metastases, and the increased migration depended on new glutathione synthesis. Furthermore, both NAC and Trolox increased the activation of the small guanosine triphosphatase (GTPase) RHOA, and blocking downstream RHOA signaling abolished antioxidant-induced migration. These results demonstrate that antioxidants and the  system play a previously unappreciated role in malignant melanoma progression.

This goes against the common idea that anti-oxidants are cancer fighters!

So what is going on?

The answer, much like a Facebook relationship status, is “its complicated”. In fact anti-oxidants can have a wide range of effects on cells, including mitosis. Many “dietary antioxidants Resveratrol and Fisetin (found in red wine), inhibit Cdks, induce a G2 arrest and prevent entry into mitosis” (Burgess et al 2014). Furthermore, we recently showed that partial inhibition of Cdk1 can dramatically disrupt to mitosis. This caused increase cancer cell death… but also increased the rate of chromosome mis-segergations. (McCloy et al 2014). These mitotic errors can drive chromosome instability (CIN), which inturn can lead to the evolution of more aggressive, invasive tumours. Understanding the genetic background of each individual cancer will be key to determining why some cancer cells die and others thrive when given antioxidants.

If you would like to know more on how common stresses such as oxidation can disrupt mitosis, you can read our recent review Stressing Mitosis to Death.

Until then, if you have cancer and are thinking of taking antioxidants, make sure you consult your oncologist as they can significantly affect the efficacy of some chemotherapeutics, and hence maybe doing more harm than good.

 

 

 

New Review Article Published!! “Mechanisms Regulating Phosphatase Specificity During Mitotic Exit”

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Great News, we have a new review article that has just been published online today in Inside the Cell!
Its Open Access, so that means its free for everyone to read!

During mitotic exit, phosphatases reverse thousands of phosphorylation events in a specific temporal order to ensure that cell division occurs correctly. This review explores how the physicochemical properties of the phosphosite and surrounding amino acids affect interactions with phosphatase/s and help determine the dephosphorylation of individual phosphorylation sites during mitotic exit.

The Full Reference and link for the Article can be found below:
Samuel Rogers, Rachael McCloy, D Neil Watkins and Andrew Burgess Mechanisms regulating phosphatase specificity and the removal of individual phosphorylation sites during mitotic exit Inside the Cell [Link]

Position available: 2016 Honours Student Project in our Lab

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Great news we are currently looking for a new honours student for 2016.

The title of the project is “Developing novel biosensors to monitor DNA damage in cancer cells”.

Its a very exciting new project incorporating cutting edge microscopy and fluorescent biosensors.

If you think you have what it takes and are interested please feel free contact myself, or UNSW SoMS.
For more information on the UNSW honours program please visit: http://medicalsciences.med.unsw.edu.au/students/soms-honours/

Below is an example of the images that will be created during the project.

New Paper Published! More data on the global phosphorylation changes during early mitotic exit

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Great news, we have another publication. This time its some extra data left over from our large mass spectrometry study we published in August in Molecular & Cellular Proteomics.

This latest work we provide additional analysis of our large proteomics dataset and identify motifs that correlated strongly with phosphorylation status for each of the major mitotic kinases.

These motifs could be used to predict the stability of phosphorylated residues in proteins of interest, and help infer potential functional roles for uncharacterized phosphorylations.

If you would like more information you can check out the full paper here [Link]. And the great news is that its OpenAccess and FREE for everyone!

Rogers, S., McCloy, R. A., Parker, B. L., Chaudhuri, R., Gayevskiy, V., Hoffman, N. J., Watkins, D. N., Daly, R. J., James, D. E., and Burgess, A. (2015) Dataset from the global phosphoproteomic mapping of early mitotic exit in human cells. Data in Brief 5, 45–52