» Articles » PMID: 16809425

Functional Uncoupling Between Ca2+ Release and Afterhyperpolarization in Mutant Hippocampal Neurons Lacking Junctophilins

Overview
Specialty Science
Date 2006 Jul 1
PMID 16809425
Citations 46
Authors
Affiliations
Soon will be listed here.
Abstract

Junctional membrane complexes (JMCs) composed of the plasma membrane and endoplasmic/sarcoplasmic reticulum seem to be a structural platform for channel crosstalk. Junctophilins (JPs) contribute to JMC formation by spanning the sarcoplasmic reticulum membrane and binding with the plasma membrane in muscle cells. In this article, we report that mutant JP double-knockout (JP-DKO) mice lacking neural JP subtypes exhibited an irregular hindlimb reflex and impaired memory. Electrophysiological experiments indicated that the activation of small-conductance Ca(2+)-activated K(+) channels responsible for afterhyperpolarization in hippocampal neurons requires endoplasmic reticulum Ca(2+) release through ryanodine receptors, triggered by NMDA receptor-mediated Ca(2+) influx. We propose that in JP-DKO neurons lacking afterhyperpolarization, the functional communications between NMDA receptors, ryanodine receptors, and small-conductance Ca(2+)-activated K(+) channels are disconnected because of JMC disassembly. Moreover, JP-DKO neurons showed an impaired long-term potentiation and hyperactivation of Ca(2+)/calmodulin-dependent protein kinase II. Therefore, JPs seem to have an essential role in neural excitability fundamental to plasticity and integrated functions.

Citing Articles

Channels, Transporters, and Receptors at Membrane Contact Sites.

Casas M, Dickson E Contact (Thousand Oaks). 2025; 7:25152564241305593.

PMID: 39742107 PMC: 11686659. DOI: 10.1177/25152564241305593.


Plasma membrane curvature regulates the formation of contacts with the endoplasmic reticulum.

Yang Y, Valencia L, Lu C, Nakamoto M, Tsai C, Liu C Nat Cell Biol. 2024; 26(11):1878-1891.

PMID: 39289582 PMC: 11567891. DOI: 10.1038/s41556-024-01511-x.


STIM Proteins: The Gas and Brake of Calcium Entry in Neurons.

Skobeleva K, Wang G, Kaznacheyeva E Neurosci Bull. 2024; 41(2):305-325.

PMID: 39266936 PMC: 11794855. DOI: 10.1007/s12264-024-01272-5.


Membrane Curvature Promotes ER-PM Contact Formation via Junctophilin-EHD Interactions.

Yang Y, Valencia L, Lu C, Nakamoto M, Tsai C, Liu C bioRxiv. 2024; .

PMID: 38979311 PMC: 11230412. DOI: 10.1101/2024.06.29.601287.


Proteomics Analysis of Pregnancy in Ewes under Heat Stress Conditions and Melatonin Administration.

Bouroutzika E, Proikakis S, Theodosiadou E, Vougas K, Katsafadou A, Tsangaris G Animals (Basel). 2024; 14(3).

PMID: 38338042 PMC: 10854642. DOI: 10.3390/ani14030400.


References
1.
Kouzu Y, Moriya T, Takeshima H, Yoshioka T, Shibata S . Mutant mice lacking ryanodine receptor type 3 exhibit deficits of contextual fear conditioning and activation of calcium/calmodulin-dependent protein kinase II in the hippocampus. Brain Res Mol Brain Res. 2000; 76(1):142-50. DOI: 10.1016/s0169-328x(99)00344-7. View

2.
Burdyga T, Wray S . Action potential refractory period in ureter smooth muscle is set by Ca sparks and BK channels. Nature. 2005; 436(7050):559-62. DOI: 10.1038/nature03834. View

3.
Takeshima H, Komazaki S, Nishi M, Iino M, Kangawa K . Junctophilins: a novel family of junctional membrane complex proteins. Mol Cell. 2000; 6(1):11-22. DOI: 10.1016/s1097-2765(00)00003-4. View

4.
Honda I, Kamiya H, Yawo H . Re-evaluation of phorbol ester-induced potentiation of transmitter release from mossy fibre terminals of the mouse hippocampus. J Physiol. 2000; 529 Pt 3:763-76. PMC: 2270214. DOI: 10.1111/j.1469-7793.2000.00763.x. View

5.
Shimuta M, Yoshikawa M, Fukaya M, Watanabe M, Takeshima H, Manabe T . Postsynaptic modulation of AMPA receptor-mediated synaptic responses and LTP by the type 3 ryanodine receptor. Mol Cell Neurosci. 2001; 17(5):921-30. DOI: 10.1006/mcne.2001.0981. View