BM
Molecular PathwaysSignalling and channel laboratory

Gene → protein → cell → circulation

Five ways a molecule reaches the whole body.

A channel converts the cell’s energy state into membrane potential and then into blood pressure within seconds. A kinase cascade converts a cytokine into transcription over hours. An antibody does nothing at all until enough copies of it stand close enough together. A protease cascade amplifies itself on any surface that fails to stop it. Each is traced from the protein to the consequence, and each fails in a different way.

Every control on this page is written into the address bar, for all five modules at once. Copy the link to hand someone this exact configuration.

Metabolic switch to vascular tone selected.

01Channel genotype

02Metabolic state

ATP 5.00 mMMgADP 18 µMfitted

03Pharmacology

A comparison state, not a prediction of natural history.

Molecule to circulation

SUR2B / Kir6.1
  1. Channel
    Open probability0.03%simulated
  2. Myocyte
    Membrane potential-34.1mVsimulated
  3. Vessel
    Arteriolar radius1.00×fitted
  4. Circulation
    Systemic resistance1.00×fitted
Mean arterial pressure94mmHgsimulated
Cardiac output5.02L/minsimulated
Action potential−0% durationillustrative

Against the reference channel: +0 mmHg, +0.00 L/min. simulated

Nucleotide dependence

3.97%010 µM8 mM ATP

At a resting energy charge the channel is almost entirely shut. Its influence comes from a very large conductance reserve, not from being open.

Resistance across the metabolic axis

SVRperfusedischaemic

The dashed line is the reference resistance. A loss-of-function channel sits above it and cannot come down — the metabolic vasodilator reserve is gone.

The channel itself

7MITVascular K_ATP · Kir6.1 with SUR2B
helixstrandloop
Four Kir6.1 pore subunits with one SUR2B — the ABCC9 product — resolved around them, with glibenclamide bound at the sulfonylurea site and ATP at the pore. A focused refinement, not a complete 4:4 octamer. RCSB 7MIT

Mechanism and evidence

Molecular lesion
The channel opens only when Mg-nucleotides occupy the SUR2B nucleotide-binding domains, so it stays largely shut while the cell is well perfused.
Systemic consequence
Normal arteriolar calibre and systemic vascular resistance.
Evidence level
reference
Vascular K_ATP cryo-EM, Sung et al. 2021

What these models cannot establish