28 questions · 12 almanac · 0 findings

Cell Signaling

How cells communicate and respond to stimuli.

Almanac A Hormone That Never Enters the Cell
  • How does adrenaline trigger changes inside a liver cell without ever crossing the cell membrane?
  • What is cyclic AMP, and why did Earl Sutherland call it a 'second messenger'?
  • Why does the second messenger concept apply to so many hormones and neurotransmitters beyond adrenaline?
  • How does the discovery of cyclic AMP connect to how caffeine affects the body?
Almanac Letters the Body Writes Itself
  • How did Stanley Cohen's discovery of epidermal growth factor extend the idea of chemical signalling between cells?
  • How can a growth-factor signal that never stops being sent lead to cancer?
Almanac Mapping How a Hormone Gets Inside
  • Why can't most hormones simply cross a cell's membrane to deliver their signal directly?
  • What role do G-proteins play in coupling a surface receptor to what happens inside the cell?
  • How does inositol trisphosphate (IP3) mobilise calcium stored inside a cell, and why does that matter for muscle contraction?
  • What did Nishizuka discover about how the lipid diacylglycerol activates protein kinase C?
Almanac The Relay Inside Every Cell's Door
  • What problem in cell signalling did scientists face before G-proteins were discovered?
  • How did Martin Rodbell's experiments on fat cells reveal that a GTP-binding relay protein was required for hormone signals to work?
  • Why do cholera toxin and pertussis toxin target G-proteins specifically, and what does that do to a cell?
  • Why do roughly a third of modern drugs target G-protein-coupled receptors?
Almanac A Pollutant the Body Uses as a Messenger
  • What did Furchgott discover about the role of endothelial cells in relaxing blood vessel walls?
  • How did Murad's finding about nitroglycerin connect to Furchgott's endothelium-derived relaxing factor?
  • Why was it surprising that nitric oxide, previously classified as an atmospheric pollutant, turned out to be a biological signalling molecule?
  • What modern treatments trace their origin to understanding nitric oxide's role in the cardiovascular system?
Almanac A Smog Gas Turns Out to Be a Messenger
  • Why had nitroglycerin been used to treat angina for over a century before anyone understood the mechanism?
  • How does nitric oxide, a small reactive gas, function as a signalling molecule that relaxes blood vessels?
  • Why did the discovery of the nitric oxide pathway overturn assumptions about what kinds of molecules can carry biological signals?
  • What later medical treatments, including for erectile dysfunction and septic shock, grew out of the nitric oxide discovery?