Biological complexity: intracellular protein delivery (Introduction)

by David Turell , Friday, August 19, 2016, 23:10 (3018 days ago) @ David Turell

Cells are constantly producing proteins for delivery into themselves or for external transport. All of this is tightly controlled as molecules are handed off:-http://phys.org/news/2016-08-scientists-decades-old-proteins-cells.html-"When things are going right in your body, it's because long strings of brand-new proteins are being folded up into just the right tangles and being delivered to just the right place within the cell at just the right time.-***-"A protein's journey begins when a piece of messenger RNA delivers instructions and a command to a ribosome, one of the tiny bulbous protein factories within the cell. The ribosome follows the recipe encoded on the mRNA - which itself was translated from the genes within your DNA - and manufactures the specific protein. The next step is where things get interesting.-"A "signal recognition particle" (SRP) latches on to the protein signal to help pilot it to the ER-"Using modern techniques and instruments that allowed them to observe the mechanism in higher resolution than previously possible, Frydman and her colleagues found that the mRNA actually contains a little bit of information that the SRP recognizes before protein production begins, and that the SRP actually waits at the exit site of the ribosome before the protein even emerges.-"'It's almost prescient; it already knows before it comes and just steps right in," Frydman said.-***-"Very important processes rely on the fidelity of where proteins have to go, Frydman said, and cells need to secrete proteins faithfully. If a particular protein stays in the cytoplasm, it could aggregate and lead to loss of healthy function or the accidental gain of unhealthy function. These gains or losses are typical of a variety of diseases, such as cystic fibrosis, cancer and Alzheimer's disease."-Comment: Just goes to show you have active the cells are and how precise. This precision is vital to life continuing. To me the systems are irreducibly complex and not explained by evolution.