Table 1.
Comparison of Intracellular Conditions with the Experimental Conditions Employed in Single-Molecule TIRF Measurements
| In Vivo Conditions | In Vitro Single-Molecule Experiment | |
|---|---|---|
| PKC | ∼0.3 μM (103, 104, 105) | 0.3 μM |
| MARCKS | ∼10 μM (14, 15) | 20 μM |
| PI3K | ∼16 nMa | 2 nM |
| ATP | ∼1 mM (106) | 1 mM |
| PIP2 | ∼1% (107, 108) | 1% |
| Na+ | 12 mM (109) | 15 mM |
| K+ | 139 mM (109) | 100 mM |
| Free Mg2+ | ∼0.5 mM (110, 111, 112) | 0.5 mM |
| Free, local Ca2+ | 1–10 μM (113, 114) | 10 μM |
a
N. Tsolakos, P. Hawkins, and L. Stephens (Babraham Institute, Cambridgeshire, UK), personal communication.