Findings illuminate animal evolution in protein function

July 27, 2015 by Eric Beidel, Virginia Commonwealth University
Findings illuminate animal evolution in protein function

Virginia Commonwealth University and University of Richmond researchers recently teamed up to explore the inner workings of cells and shed light on the 400–600 million years of evolution between humans and early animals such as sponges.

In a new paper published in the Journal of Biological Chemistry, the team reported its discovery that humans and other vertebrates have key components needed for cell communication and function that were absent from the sponge and other distant relatives.

The paper, "Nature's Mutations Evolved a High Affinity PIP2 Binding Site in Vertebrate Inwardly Rectifying Potassium Channels," describes how the study of "nature's mutations" can explain the functional consequences of evolution in distantly related animal species.

The team was led by Linda Boland, Ph.D., chair of the Department of Biology at the University of Richmond, and Diomedes Logothetis, Ph.D., professor and chair of the Department of Physiology and Biophysics at VCU's School of Medicine.

Ion channels allow cells to pass electricity back and forth. Researchers looked specifically at Kir channels, which conduct potassium ions out of cells and help maintain normal cellular activity.

For the most part, human and sponge ion channels are the same. The recent paper explores one key difference that researchers now believe developed about the time the first animals evolved. This means the changes in question occurred more recently than the appearance 2 billion years ago of complex cells, providing more evidence as to when and how the first animals evolved from single-cell organisms, or prokaryotes.

"Evidence suggests that eukaryotic cells evolved from ," Boland said. "Among eukaryotes, when sponges evolved is subject to some debate, but they seem to be positioned at a key point in animal evolution."

All vertebrate Kir channels are activated by PIP2, a phospholipid in cell membranes that "is a master regulator of protein function," Logothetis said, and therefore triggers biochemical reactions key to intracellular function.

The sponge Kir , however, does not share this high affinity with PIP2 as it lacks two amino acids necessary for the interaction.

Researchers compared amino acids in both sponge and mammal Kir channels. They found that introducing mammalian amino acid residue into the sponge channel makes it highly sensitive to PIP2, Logothetis said.

Properly operating Kir channels are critical for cell function. Malfunctions in these channels have been cited in several diseases, including Anderson-Tawil syndrome, which causes muscle weakness, changes in heart rhythm and developmental abnormalities.

"Understanding more about the critical components of the PIP2 binding site could present some unique therapeutic targets for regulation of the human ion channel," Boland said.

What started as a strong collaboration between VCU and the University of Richmond has expanded to include a lab at the University of San Diego, widening the team's scope.

Researchers now are focused on finding additional differences between the sponge and vertebrate and also studying the channels of other invertebrates such as cnidarians, the first to possess a nervous system.

They also will examine the origins of sodium and calcium channels that are needed for action potential generation, a phenomenon marked by transfer of electricity from one cell to another.

Explore further: A new concept in the field of voltage-gated ion channels

More information: "Nature's Mutations Evolved a High Affinity PIP2 Binding Site in Vertebrate Inwardly Rectifying Potassium Channels" J. Biol. Chem. jbc.M115.640409. First Published on May 8, 2015, DOI: 10.1074/jbc.M115.640409

Related Stories

A new concept in the field of voltage-gated ion channels

August 21, 2012

(Phys.org) -- Virginia Commonwealth University School of Medicine researchers have uncovered a novel way by which the activity of voltage-gated potassium channels are regulated, according to a study published online last ...

Fitting Kv potassium channels in the PIP2 puzzle

August 27, 2012

A recent study in the Journal of General Physiology brings new insights to an area of ion channel regulation: whether voltage-gated potassium (Kv) channels can be regulated by physiological changes to PIP2.

Studying dynamics of ion channels

May 18, 2015

Scientists from the Vaziri lab at the Vienna Biocenter, together with colleagues at the Institute for Biophysical Dynamics at the University of Chicago, have developed a method using infrared spectroscopy and atomistic modeling ...

Recommended for you

Can China keep it's climate promises?

March 26, 2019

China can easily meet its Paris climate pledge to peak its greenhouse gas emissions by 2030, but sourcing 20 percent of its energy needs from renewables and nuclear power by that date may be considerably harder, researchers ...

In the Tree of Life, youth has its advantages

March 26, 2019

It's a question that has captivated naturalists for centuries: Why have some groups of organisms enjoyed incredibly diversity—like fish, birds, insects—while others have contained only a few species—like humans.

Cellular microRNA detection with miRacles

March 26, 2019

MicroRNAs (miRNAs) are short noncoding regulatory RNAs that can repress gene expression post-transcriptionally and are therefore increasingly used as biomarkers of disease. Detecting miRNAs can be arduous and expensive as ...

6 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

Vietvet
3.7 / 5 (3) Jul 27, 2015
Here come the young earth creationist:

JVK
viko-mix
ren82
And others in 1-2-3-
Vietvet
3.7 / 5 (3) Jul 27, 2015
I should have added @Noumenon
Noumenon
2.3 / 5 (3) Jul 28, 2015
I should have added @Noumenon


I believe in evolution and science.
antigoracle
1 / 5 (2) Jul 28, 2015
Here come the young...blah....blah..blah..

How did this one make it into the gene pool?
Either Darwin was wrong, or humans have "broken" evolution.
Vietvet
3.7 / 5 (3) Jul 28, 2015
I should have added @Noumenon


I believe in evolution and science.


Got it. You just have a penchant for down rating comments critical of young earth creationists.
Noumenon
2.3 / 5 (3) Jul 29, 2015
I should have added @Noumenon


I believe in evolution and science.


Got it. You just have a penchant for down rating comments critical of young earth creationists.


I'm an atheist who down rates some without explanation,.... likely the only thing we have in common.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.