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Emerging Concepts in Ion Channel Biophysics
Poster Abstracts
63
70-POS
Board 70
Voltage- and Ca
2+
- Activated Potassium Channels as a Part of Ca
2+
Toolkit in Healthy T
Cells and Leukemic Cell Lines.
Juan Salvador Valle Reyes
, Igor Pottosin, Georgina Valencia Cruz, Liliana Liñan Rico, Oxana
Dobrovinskaya.
University of Colima, University Center for Biomedical Research, Colima, México n/a,
Coyoacan, Mexico.
Potassium channels play key roles in shaping electrical signals in both excitable and non-excitable
cells. Yet their impact on Ca
2+
entry in excitable and non-excitable cells is opposite: cessation or
maintenance of Ca2
+
entry, respectively. In lymphocytes Ca2
+
entry is dominated by inward-
rectifying CRAC current, which for its sustained activity requires membrane repolarization,
mediated primarily by Kv and KCa channels. This Ca
2+
entry controls maturation, activation,
differentiation and apoptosis. In the present work we analysed Kv and KCa currents in acute T
leukemic (Jurkat, CEM and, MOLT) and healthy T cells. Our analysis shows moderate but
significant differences in Kv (Kv1.3 in all cases) channels’ activation and inactivation parameters.
KCa currents were represented by KCa3.1 channels in all cases except Jurkat cells, where they
were mediated by KCa2.2 channels. Strikingly, Jurkat cells, which over 50 years served as a
prototypic model for acute T leukemia, displayed 10-times lower density of Kv and KCa currents
compared to previously underexplored CEM and MOLT cell lines. As for KCa density in CEM
and MOLT cells, it was comparable to that in activated healthy T cells and manifold higher as
compared to resting T cells. These differences will be discussed in the context of Ca
2+
signaling
during T cells activation and leukemogenesis. Supported by CONACyT, grants CB-238689 (OD),
CB-220793 (IP), Fronteras in Ciencia 140 (OD).