Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


New Technique Maps Elusive Chemical Markers on Proteins


Unveiling how the 20,000 or so proteins in the human body work—and malfunction—is the key to understanding much of health and disease. Now, Salk researchers developed a new technique that allows scientists to better understand an elusive step critical in protein formation.

The new method, described on July 2, 2015 in the journal Cell, allows researchers to map critical chemical tags—called phosphates—that bond to amino acids (the building blocks of proteins) in the final stages of creating a protein.

Salk Institute

Caption: Salk scientists developed antibodies that tag essential chemicals involved in protein action. In this dividing cell, the new antibody (green) marks discrete areas of a critical but elusive chemical reaction that happens when cells divide (DNA in blue and tubulin, a protein needed for cell division, in red).

When a cell produces a protein, molecular synthetic machinery first pieces together the amino acids into a long strand that bends and folds as it lengthens. Enzymes then gather around the structure to make final tweaks—trimming the protein or adding chemical tags. Among these last modifications is phosphorylation—or addition of phosphate—of individual amino acids to change the protein’s function. Until now, pinpointing exactly where (and why) all those phosphates are added has been tricky.

“We know that 9 out of the 20 amino acids can be phosphorylated, but we know very little about most of them because they’re so hard to study,” says Tony Hunter, American Cancer Society Professor, holder of the Dulbecco Chair in the Salk’s Molecular and Cell Biology Laboratory and senior author of the new paper.

When phosphate is added to three particular amino acids—serine, threonine and tyrosine—it forms a strong chemical bond. Researchers can easily identify the location of these phosphates. But when the other six amino acids are phosphorylated, the phosphate is only loosely attached to each amino acid, causing problems for researchers trying to glean what happens in these cases. One of these amino acids, called histidine (or phosphohistidine once a phosphate is added), has been particularly tough to study.

“With those strong phosphorylation events, you can label cells, isolate proteins and analyze the proteins in various ways to find out where the phosphates are,” says Hunter. “You can’t do that with phosphohistidine because it’s so unstable it falls apart as you’re trying to isolate the proteins.”

Hunter and his collaborators realized that to study this unstable interaction, they would have to use a trick to make a stronger bond between phosphate and histidine. So they used a special kind of modified phosphate, called phosphonate, engineered to bind more tightly to either of the two spots on a histidine amino acid where phosphate can be added. Then, they developed antibodies that specifically recognize these stable phosphohistidine analogues, but also detect authentic phosphohistidine in proteins.

To test these new tools, the team added their phosphohistidine antibodies to a collection of different mammalian cells grown on slides and observed where in the cell the antibodies bound, which indicates parts of cells that have high levels of proteins with phosphohistidines.

“The thing that surprised us most is that when we stained the cells with the new antibodies, we saw discrete areas within the cells that had high levels of histidine phosphorylation, particularly when they were undergoing mitosis, the stage at which cells divide into two daughter cells,” says Hunter. They don’t yet know exactly why that is, but plan to continue to explore these results as well as detect the phosphorylation of other amino acids.

The team expects these antibody tools to be useful to other labs aiming to determine whether proteins of interest have any phosphohistidines.

The new method is “fairly easy for any lab to use,” Hunter says. “It doesn’t require a special instrument or anything, so I think it may be fairly quickly adopted.”

Other researchers on the study were Stephen Rush Fuhs, Jill Meisenhelder, Aaron Aslanian, Li Ma, Anna Zagorska and Greg Lemke, of the Salk Institute; Magda Stankova, Alan Binnie, Fahad Al-Obeidi and Jacques Mauger, of Sanofi; and John R. Yates III of the Scripps Research Institute.

The work and the researchers involved were supported by the National Institutes of Health, a Salk Institute Innovation Grant and the Helmsley Center for Genomic Medicine.

About the Salk Institute for Biological Studies:
The Salk Institute for Biological Studies is one of the world's preeminent basic research institutions, where internationally renowned faculty probes fundamental life science questions in a unique, collaborative and creative environment. Focused both on discovery and on mentoring future generations of researchers, Salk scientists make groundbreaking contributions to our understanding of cancer, aging, Alzheimer's, diabetes and infectious diseases by studying neuroscience, genetics, cell and plant biology, and related disciplines. Faculty achievements have been recognized with numerous honors, including Nobel Prizes and memberships in the National Academy of Sciences. Founded in 1960 by polio vaccine pioneer Jonas Salk, MD, the Institute is an independent nonprofit organization and architectural landmark.

Contact Information
Salk Communications

Salk Communications | newswise
Further information:

More articles from Life Sciences:

nachricht Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München

nachricht Second research flight into zero gravity
21.10.2016 | Universität Zürich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>