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Different roles for the cyclic nucleotide binding domain and amino terminus in assembly and expression of hyperpolarization-activated, cyclic nucleotide-gated channels.
J Biol Chem. 2002 Aug 16; 277(33):29634-42.JB

Abstract

In mammalian heart and brain, pacemaker currents are produced by hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels, which probably exist as heteromeric assemblies of different subunit isoforms. To investigate the molecular domains that participate in assembly and membrane trafficking of HCN channels, we have used the yeast two-hybrid system, patch clamp electrophysiology, and confocal microscopy. We show here that the N termini of the HCN1 and HCN2 isoforms interacted and were essential for expression of functional homo- or heteromeric channels on the plasma membrane of Chinese hamster ovary cells. We also show that the cyclic nucleotide binding domain (CNBD) of HCN2 was required for the expression of functional homomeric channels. This expression was dependent on a 12-amino acid domain corresponding to the B-helix in the CNBD of the catabolite activator protein. However, co-expression with HCN1 of an HCN2 deletion mutant lacking the CNBD rescued surface immunofluorescence and currents, indicating that a CNBD need not be present in each subunit of a heteromeric HCN channel. Furthermore, neither CNBDs nor other COOH-terminal domains of HCN1 and HCN2 interacted in yeast two-hybrid assays. Thus, interaction between NH(2)-terminal domains is important for HCN subunit assembly, whereas the CNBD is important for functional expression, but its absence from some subunits will still allow for the assembly of functional channels.

Authors+Show Affiliations

Ion Channel Laboratory, School of Kinesiology, Simon Fraser University, Burnaby, British Columbia V5A 1S6 Canada.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

12034718

Citation

Proenza, Catherine, et al. "Different Roles for the Cyclic Nucleotide Binding Domain and Amino Terminus in Assembly and Expression of Hyperpolarization-activated, Cyclic Nucleotide-gated Channels." The Journal of Biological Chemistry, vol. 277, no. 33, 2002, pp. 29634-42.
Proenza C, Tran N, Angoli D, et al. Different roles for the cyclic nucleotide binding domain and amino terminus in assembly and expression of hyperpolarization-activated, cyclic nucleotide-gated channels. J Biol Chem. 2002;277(33):29634-42.
Proenza, C., Tran, N., Angoli, D., Zahynacz, K., Balcar, P., & Accili, E. A. (2002). Different roles for the cyclic nucleotide binding domain and amino terminus in assembly and expression of hyperpolarization-activated, cyclic nucleotide-gated channels. The Journal of Biological Chemistry, 277(33), 29634-42.
Proenza C, et al. Different Roles for the Cyclic Nucleotide Binding Domain and Amino Terminus in Assembly and Expression of Hyperpolarization-activated, Cyclic Nucleotide-gated Channels. J Biol Chem. 2002 Aug 16;277(33):29634-42. PubMed PMID: 12034718.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Different roles for the cyclic nucleotide binding domain and amino terminus in assembly and expression of hyperpolarization-activated, cyclic nucleotide-gated channels. AU - Proenza,Catherine, AU - Tran,Neil, AU - Angoli,Damiano, AU - Zahynacz,Kristin, AU - Balcar,Petr, AU - Accili,Eric A, Y1 - 2002/05/28/ PY - 2002/5/30/pubmed PY - 2002/9/21/medline PY - 2002/5/30/entrez SP - 29634 EP - 42 JF - The Journal of biological chemistry JO - J Biol Chem VL - 277 IS - 33 N2 - In mammalian heart and brain, pacemaker currents are produced by hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels, which probably exist as heteromeric assemblies of different subunit isoforms. To investigate the molecular domains that participate in assembly and membrane trafficking of HCN channels, we have used the yeast two-hybrid system, patch clamp electrophysiology, and confocal microscopy. We show here that the N termini of the HCN1 and HCN2 isoforms interacted and were essential for expression of functional homo- or heteromeric channels on the plasma membrane of Chinese hamster ovary cells. We also show that the cyclic nucleotide binding domain (CNBD) of HCN2 was required for the expression of functional homomeric channels. This expression was dependent on a 12-amino acid domain corresponding to the B-helix in the CNBD of the catabolite activator protein. However, co-expression with HCN1 of an HCN2 deletion mutant lacking the CNBD rescued surface immunofluorescence and currents, indicating that a CNBD need not be present in each subunit of a heteromeric HCN channel. Furthermore, neither CNBDs nor other COOH-terminal domains of HCN1 and HCN2 interacted in yeast two-hybrid assays. Thus, interaction between NH(2)-terminal domains is important for HCN subunit assembly, whereas the CNBD is important for functional expression, but its absence from some subunits will still allow for the assembly of functional channels. SN - 0021-9258 UR - https://www.unboundmedicine.com/medline/citation/12034718/Different_roles_for_the_cyclic_nucleotide_binding_domain_and_amino_terminus_in_assembly_and_expression_of_hyperpolarization_activated_cyclic_nucleotide_gated_channels_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0021-9258(18)75624-X DB - PRIME DP - Unbound Medicine ER -