Receptor Proteins Hold Clues to Antibiotic Resistance in MRSA, Scientists Say

Sci-News.com ^ | May 28, 2013 | Sergio Prostak

[neverdem]

A team of researchers led by Dr Angelika Gründling from Imperial College London has discovered 4 proteins that act as receptors for an essential signalling molecule in bacteria such as the methicillin-resistant Staphylococcus aureus (MRSA).

This micrograph shows methicillin-resistant Staphylococcus aureus (Janice Haney Carr / CDC / Jeff Hageman / M.H.S.)

A recently discovered molecule called cyclic diadenylate monophosphate (c-di-AMP for short) appears to play a vital role as a messenger in many bacteria, carrying signals between parts of the cell. There is evidence that strains with more c-di-AMP are more resistant to antibiotics.

But until now, very little was known about what processes in cells are regulated by c-di-AMP.

“What makes this molecule special and a bit different from others like it is that there is now growing evidence that many bacteria need to produce this molecule in order to grow and divide, so it’s an essential component of the cell,” explained Dr Gründling, who is the senior author of the study published in the Proceedings of the National Academy of Sciences.

Signalling molecules work by binding to specific receptor proteins, which act as switches for cellular functions.

“So the real key to understanding what pathways are controlled by c-di-AMP, and therefore help us to understand why this molecule is important for the growth of bacteria, is to find these target proteins,” Dr Gründling said.

In the new study, Dr Gründling’s team pinpointed four receptors for c-di-AMP in Staphylococcus aureus. Similar proteins are found in many other bacterial species, several of which can also cause disease in humans.

“This is really exciting news for the field, as we now have the first clues as to which cellular pathways we need to focus on in order to understand why this molecule is so important for the growth of Staphylococcus aureus,” said first author Dr Rebecca Corrigan, also from Imperial College London.

“We hope that these findings can be exploited in the future to develop new antibiotics that target the cellular pathways controlled by c-di-AMP. Such drugs might be effective against a broad spectrum of bacteria.”

“There is now also increasing evidence that Staphylococcus aureus strains with high c-di-AMP levels show increased resistance to methicillin-type antibiotics. This indicates that c-di-AMP might help bacteria to better survive antibiotic treatment and by inhibiting c-di-AMP synthesis we might be able to increase the effectiveness of certain antibiotics,” Dr Gründling said.

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Bibliographic information: Rebecca M. Corrigan et al. Systematic identification of conserved bacterial c-di-AMP receptor proteins. PNAS, published online before print May 13, 2013; doi: 10.1073/pnas.1300595110

[Jimmy4Toes]

Jimmy4Toes is brought to you by MRSA. Wish they learned of this earlier.

[Uri’el-2012]

What about MSSA ?

[arthurus]

If it is not on the market before the end of this year it goes away with obamacare.