TY - JOUR
T1 - Regulation of the neuronal KCNQ2 channel by Src - A dual rearrangement of the cytosolic termini underlies bidirectional regulation of gating
AU - Siloni, Sivan
AU - Singer-Lahat, Dafna
AU - Esa, Moad
AU - Tsemakhovich, Vlad
AU - Chikvashvili, Dodo
AU - Lotan, Ilana
N1 - Publisher Copyright:
© 2015.
PY - 2015
Y1 - 2015
N2 - Neuronal M-type K+ channels are heteromers of KCNQ2 and KCNQ3 subunits, and are found in cell bodies, dendrites and the axon initial segment, regulating the firing properties of neurons. By contrast, presynaptic KCNQ2 homomeric channels directly regulate neurotransmitter release. Previously, we have described a mechanism for gating downregulation of KCNQ2 homomeric channels by calmodulin and syntaxin1A. Here, we describe a new mechanism for regulation of KCNQ2 channel gating that is modulated by Src, a non-receptor tyrosine kinase. In this mechanism, two concurrent distinct structural rearrangements of the cytosolic termini induce two opposing effects: upregulation of the single-channel open probability, mediated by an N-terminal tyrosine, and reduction in functional channels, mediated by a C-terminal tyrosine. In contrast, Src-mediated regulation of KCNQ3 homomeric channels, shown previously to be achieved through the corresponding tyrosine residues, involves the N-terminal-tyrosine-mediated downregulation of the open probability, rather than an upregulation. We argue that the dual bidirectional regulation of KCNQ2 functionality by Src, mediated through two separate sites, means that KCNQ2 can be modified by cellular factors that might specifically interact with either one of the sites, with potential significance in the fine-tuning of neurotransmitters release at nerve terminals.
AB - Neuronal M-type K+ channels are heteromers of KCNQ2 and KCNQ3 subunits, and are found in cell bodies, dendrites and the axon initial segment, regulating the firing properties of neurons. By contrast, presynaptic KCNQ2 homomeric channels directly regulate neurotransmitter release. Previously, we have described a mechanism for gating downregulation of KCNQ2 homomeric channels by calmodulin and syntaxin1A. Here, we describe a new mechanism for regulation of KCNQ2 channel gating that is modulated by Src, a non-receptor tyrosine kinase. In this mechanism, two concurrent distinct structural rearrangements of the cytosolic termini induce two opposing effects: upregulation of the single-channel open probability, mediated by an N-terminal tyrosine, and reduction in functional channels, mediated by a C-terminal tyrosine. In contrast, Src-mediated regulation of KCNQ3 homomeric channels, shown previously to be achieved through the corresponding tyrosine residues, involves the N-terminal-tyrosine-mediated downregulation of the open probability, rather than an upregulation. We argue that the dual bidirectional regulation of KCNQ2 functionality by Src, mediated through two separate sites, means that KCNQ2 can be modified by cellular factors that might specifically interact with either one of the sites, with potential significance in the fine-tuning of neurotransmitters release at nerve terminals.
KW - FRET
KW - Gating
KW - KCNQ2
KW - Open probability
KW - Src
UR - http://www.scopus.com/inward/record.url?scp=84946045770&partnerID=8YFLogxK
U2 - 10.1242/jcs.173922
DO - 10.1242/jcs.173922
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C2 - 26275828
AN - SCOPUS:84946045770
SN - 0021-9533
VL - 128
SP - 3489
EP - 3501
JO - Journal of Cell Science
JF - Journal of Cell Science
IS - 18
ER -