Navigation Links
Danish researchers release ground-breaking knowledge about calcium pumps in cells
Date:10/25/2012

When animals and plants are exposed to influences such as bacterial attack, odour and cold, calcium ions flow into the cells. The calcium provides the cells with a signal about what is going on outside, but as high concentrations of calcium are toxic to the cells, it must be quickly pumped out again. Researchers from the Danish National Research Foundation's PUMPkin Centre at both the University of Copenhagen and Aarhus University have now shown that calcium pumps in the cell's outer membrane adjust the pump speed very accurately to the calcium concentration. These findings have just been published in the prestigious journal Nature.

The calcium pump is located in the thin membrane that surrounds the cells of humans, animals and plants. Leading researchers from Aarhus University and the University of Copenhagen have now provided new information of how the calcium pump regulates the amount of calcium in the cells. This amount is critical to the health and survival of the cell.

"It turns out that the calcium pump can accurately measure the cell's calcium content and adjust its speed in accordance with this information. This prevents the concentration of calcium ions in the cytoplasm from reaching a critical concentration that damages the cells. The calcium pump is inactive when the concentration of calcium is low, but it is activated stepwise when the calcium concentration increases," say Postdoctoral Fellows Henning Tidow and Lisbeth Rosager Poulsen, who took part in the joint research project.

The researchers' starting point was the calcium pump located in the cell membrane of the model plant thale cress (Arabidopsis thaliana), but the regulatory mechanism also applies to the corresponding calcium pump in humans and animals.

Calcium pumps bind two calmodulin proteins

Previous studies have shown that calcium pumps in both animals and plants work together with a protein called calmodulin. When there are many calcium ions in a cell, some of these bind to calmodulin, which is thereby able to activate the calcium pump.

"We purified the part of the calcium pump that interacts with calcium-activated calmodulin, and we managed to crystallise a protein complex. To our great surprise, we found that the calcium pump binds two calmodulin proteins, and not just one as always assumed," explains Dr Tidow.

Calcium pump with three-step regulation

The fact that two calmodulin proteins are involved in the regulation of the calcium pump activity means that the calcium pump has three steps. It is switched off when no calcium-activated calmodulin is bound, it pumps at medium speed when binding occurs at one calmodulin protein, and it pumps at full speed when both calmodulin proteins are bound.

"Calcium pumps need considerable energy to transport calcium out of the cell. It is therefore important that they are only activated when there is a need to remove calcium. With two calmodulin-binding domains in the calcium pump, the cell can adjust the transportation to be energy efficient, at the same time as being able to quickly reduce the number of calcium ions if the concentration approaches a toxic level," Dr Poulsen concludes.

Mathematics reveals biological function

The researchers also used mathematical network modelling to further identify whether the calcium pump works differently depending on whether it is activated by zero, one or two calmodulin proteins. This revealed another characteristic of calcium pump regulation of calcium in the cell.

"We could show that the cell only responded to incoming calcium when concentrations above carefully defined threshold values were found. This may be important for the way cells define their status in the circadian rhythm or during cell division, for example," concludes Dr Tidow.


'/>"/>

Contact: Press Officer Carl Hagman
cahag@adm.ku.dk
45-21-62-34-31
University of Copenhagen
Source:Eurekalert

Related biology news :

1. New Danish fungal species discovered
2. CU-Boulder researchers uncover new target for cancer research
3. Columbia researchers report novel approach for single molecule electronic DNA sequencing
4. Researchers develop new stamping process to pattern biomolecules at high resolution
5. Mount Sinai researchers awarded Provocative Questions grant from National Cancer Institute
6. RUB researchers clarify catalysis mechanism of cell growth protein Ras
7. Researchers find our inner reptile hearts
8. Researchers develop rapid method to measure carbon footprints
9. Researchers reveal a chemo-resistant cancer stem cell as cancers Achilles heel
10. Researchers use banker plants to help battle whitefly pests
11. Researchers find first evidence for a genetic cause for Barretts oesophagus
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/15/2016)... New York , March 15, 2016 ... new market report published by Transparency Market Research "Digital Door ... Trends and Forecast 2015 - 2023," the global digital door ... US$ 731.9 Mn in 2014 and is forecast to grow ... 2023. Growth of micro, small and medium enterprises (MSMEs) across ...
(Date:3/11/2016)... , March 11, 2016 ... market research report "Image Recognition Market by Technology (Pattern ... and Advertising), by Deployment Type (On-Premises and Cloud), by ... 2022", published by MarketsandMarkets, the global market is expected ... USD 29.98 Billion by 2020, at a CAGR of ...
(Date:3/9/2016)... Fla. , March 9, 2016  Crossmatch ... authentication and enrollment solutions, today announced the addition ... ® Altus multi-factor authentication platform. New ... InfoSec managers to step-up security where it,s needed ... Washington, DC . --> ...
Breaking Biology News(10 mins):
(Date:5/27/2016)... , ... May 27, 2016 , ... Weeks after hosting ... in Phoenix, Dr. Michael Fitzmaurice, hand surgeon and founder of the Fitzmaurice Hand Institute, ... The Wrist MRI machine is a state-of-the-art technology and only 1 of about 3 ...
(Date:5/27/2016)... At present, the Biotech sphere is in a ... volatility is what makes this industry interesting to consider. Here ... (NASDAQ: SNTA ), CTI BioPharma Corp. (NASDAQ: ... and Heat Biologics Inc. (NASDAQ: HTBX ). Sign ... these stocks at: http://www.activewallst.com/register/ ...
(Date:5/26/2016)... Despite the volatility that continues to envelop the ... research on ActiveWallSt.com directs the investor community,s focus on the ... ), Cerus Corp. (NASDAQ: CERS ), Arrowhead Pharmaceuticals ... Inc. (NASDAQ: FPRX ). Register with us today ... On Wednesday, shares in Massachusetts ...
(Date:5/25/2016)... ... May 25, 2016 , ... Lajollacooks4u has become a rising hotspot ... rated one of its top attractions. Fortune 500 companies, such as Illumina, Hewlett-Packard, ... unique and intimate team-building experience. , Each event kicks off with an olive oil ...
Breaking Biology Technology: