Ondacova K, Karmazinova M, Lazniewska J, Weiss N, Lacinova L. Modulation of Cav3.2 T-type calcium channel permeability by asparagine-linked glycosylation.
Channels (Austin) 2016;
10:175-84. [PMID:
26745591 DOI:
10.1080/19336950.2016.1138189]
[Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Low-voltage-gated T-type calcium channels are expressed throughout the nervous system where they play an essential role in shaping neuronal excitability. Defects in T-type channel expression have been linked to various neuronal disorders including neuropathic pain and epilepsy. Currently, little is known about the cellular mechanisms controlling the expression and function of T-type channels. Asparagine-linked glycosylation has recently emerged as an essential signaling pathway by which the cellular environment can control expression of T-type channels. However, the role of N-glycans in the conducting function of T-type channels remains elusive. In the present study, we used human Cav3.2 glycosylation-deficient channels to assess the role of N-glycosylation on the gating of the channel. Patch-clamp recordings of gating currents revealed that N-glycans attached to hCav3.2 channels have a minimal effect on the functioning of the channel voltage-sensor. In contrast, N-glycosylation on specific asparagine residues may have an essential role in the conducting function of the channel by enhancing the channel permeability and / or the pore opening of the channel. Our data suggest that modulation of N-linked glycosylation of hCav3.2 channels may play an important physiological role, and could also support the alteration of T-type currents observed in disease states.
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