Biological complexity: evolution of ion exchange pathways (Introduction)

by David Turell , Monday, July 27, 2015, 15:23 (3407 days ago) @ David Turell

Cells use ions from potassium or sodium to communicate. These have changed during evolution from sponges to more complex organism:-http://phys.org/news/2015-07-illuminate-animal-evolution-protein-function.html-"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 prokaryotic cells," 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 channel, 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. -Comment: The enormous complexity of each single cell in our bodies is slowly being elucidated. We really know just a little so far, but it is not difficult to imagine what the whole story will look like 50 years from now, an amazing biologic machinery automatically functioning, each contributing to the living whole organism in perfect coordination. This is why cells look like they 'think'.-Our multicellular selves came from single cells, as the article states. Think how self-reliant single cell organisms have to be from the start of life! Metabolize food, avoid danger and reproduce, and this can all be done automatically with the right chemical reactions if the DNA has enough initial information controls.