Effects of truncated calcium channel constructs on the expression of voltage-gated calcium channel currents
| Full-length channel | Truncated domain or construct | Cell type (units) | Control peak current (n) | Current plus truncated domain (n) | Percentage of reduction in current |
|---|---|---|---|---|---|
| Cav2.2/α2δ-2/β1b | Cav2.2-Dom I | Oocytes (μA) | −1.64 ± 0.11 (62) | −0.21 ± 0.04 (46) | 87.0 ± 2.2** |
| Cav2.2/α2δ-2/β1b | Kir2.1-AAA | Oocytes (μA) | −0.81 ± 0.14 (30) | −0.87 ± 0.10 (35) | −2.4 ± 10.7 |
| Cav2.1/α2δ-2/β4 | Cav2.1-P1217fs | Oocytes (μA) | −0.68 ± 0.14 (22) | −0.05 ± 0.01 (20) | 92.5 ± 1.8** |
| Cav2.1/α2δ-2/β4 | Cav2.1-P1217fs | COS-7 (pA/pF) | −46.4 ± 11.7 (9) | −2.9 ± 1.7 (3) | 93.8 ± 3.7** |
| Cav2.1/α2δ-2/β4 | Cav2.2-Dom I-II | tsA201 (pA/pF) | −150.4 ± 47.0 (12) | −90.2 ± 24.9 (12) | 40.1 ± 16.6* |
| Cav2.3/α2δ-1/β1b | Cav2.2-Dom I-II | COS-7 (pA/pF) | −69.0 ± 17.7 (8) | −35.7 ± 14.1 (9) | 48.2 ± 20.5* |
| Cav2.2/α2δ-2/β1b | Cav2.1-P1217fs | tSA201 (pA/pF) | −195.1 ± 42.0 (11) | −97.1 ± 25.9 (17) | 50.2 ± 13.2* |
| Cav3.1 | Cav3.1-Dom I | tsA-201 (pA/pF) | −59.4 ± 10.3 (27) | −21.9 ± 3.9 (24) | 63.0 ± 6.6** |
| Cav3.1 | Cav3.1-Dom I-II | tsA-201 (pA/pF) | −86.2 ± 16.5 (25) | −43.3 ± 9.8 (25) | 49.9 ± 11.4* |
| Cav3.2 | Cav3.2-Dom I | tsA-201 (pA/pF) | −75.4 ± 11.3 (15) | −8.0 ± 0.98 (9) | 89.4 ± 1.3** |
| Cav3.1 | Cav2.2-Dom I | tsA-201 (pA/pF) | −63.1 ± 21.8 (14) | −49.9 ± 10.8 (11) | 20.9 ± 17.0 |
| Cav3.1 | Cav2.2-Dom I-II | COS-7 (pA/pF) | −39.5 ± 10.0 (11) | −44.0 ± 13.6 (11) | −11.5 ± 34.5 |
| Cav3.1 | Cav2.1-P1217fs | COS-7 (pA/pF) | −41.3 ± 9.8 (10) | −41.6 ± 10.7 (10) | −0.66 ± 26.0 |
| Cav2.2/α2δ-2/β1b | Cav3.1-Dom I | tsA-201 (pA/pF) | −84.5 ± 23.7 (10) | −96.0 ± 31.7 (8) | −13.5 ± 37.5 |
All conditions in the same row were performed in parallel to circumvent variability between batches of cells or oocytes. Data were confirmed in at least two different experiments. The inhibition was determined for the mean peak IBa. For oocytes, this was O mV for Cav2.2, −5 mV for Cav2.1 and Cav1.2, and +5 mV for Cav1.2, in 5 mm Ba2+. In mammalian cells, peak IBa was + 10 mV for Cav2.1, +20 mV for Cav2.2, and −10 mV for Cav3.1 and Cav3.2, all in 10 mm Ba2+. Statistical significance: **p <0.0001;*p <0.05; Student's t test.