Dataset Information

PRRT2 modulates presynaptic Ca²⁺ influx by interacting with P/Q-type channels.

ABSTRACT: Loss-of-function mutations in proline-rich transmembrane protein-2 (PRRT2) cause paroxysmal disorders associated with defective Ca²⁺ dependence of glutamatergic transmission. We find that either acute or constitutive PRRT2 deletion induces a significant decrease in the amplitude of evoked excitatory postsynaptic currents (eEPSCs) that is insensitive to extracellular Ca²⁺ and associated with a reduced contribution of P/Q-type Ca²⁺ channels to the EPSC amplitude. This synaptic phenotype parallels a decrease in somatic P/Q-type Ca²⁺ currents due to a decreased membrane targeting of the channel with unchanged total expression levels. Co-immunoprecipitation, pull-down assays, and proteomics reveal a specific and direct interaction of PRRT2 with P/Q-type Ca²⁺ channels. At presynaptic terminals lacking PRRT2, P/Q-type Ca²⁺ channels reduce their clustering at the active zone, with a corresponding decrease in the P/Q-dependent presynaptic Ca²⁺ signal. The data highlight the central role of PRRT2 in ensuring the physiological Ca²⁺ sensitivity of the release machinery at glutamatergic synapses.

SUBMITTER: Ferrante D

PROVIDER: S-EPMC8220258 | biostudies-literature | 2021 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

PRRT2 modulates presynaptic Ca2+ influx by interacting with P/Q-type channels.

Ferrante Daniele D Sterlini Bruno B Prestigio Cosimo C Marte Antonella A Corradi Anna A Onofri Franco F Tortarolo Giorgio G Vicidomini Giuseppe G Petretto Andrea A Muià Jessica J Thalhammer Agnes A Valente Pierluigi P Cingolani Lorenzo A LA Benfenati Fabio F Baldelli Pietro P

Cell reports 20210601 11

Loss-of-function mutations in proline-rich transmembrane protein-2 (PRRT2) cause paroxysmal disorders associated with defective Ca2+ dependence of glutamatergic transmission. We find that either acute or constitutive PRRT2 deletion induces a significant decrease in the amplitude of evoked excitatory postsynaptic currents (eEPSCs) that is insensitive to extracellular Ca2+ and associated with a reduced contribution of P/Q-type Ca2+ channels to the EPSC amplitude. T ...[more]

PMID: 34133925

Similar Datasets

Project description:Tuberous sclerosis complex (TSC) is a multisystem developmental disorder characterized by hamartomas in various organs, such as the brain, lungs, and kidneys. Epilepsy, along with autism and intellectual disability, is one of the neurologic impairments associated with TSC that has an intimate relationship with developmental outcomes and quality of life. Sustained activation of the mammalian target of rapamycin (mTOR) via TSC1 or TSC2 mutations is known to be involved in the onset of epilepsy in TSC. However, the mechanism by which mTOR causes seizures remains unknown. In this study, we showed that, human induced pluripotent stem cell-derived TSC2-deficient (TSC2 -/-) neurons exhibited elevated neuronal activity with highly synchronized Ca2+ spikes. Notably, TSC2 -/- neurons presented enhanced Ca2+ influx via L-type Ca2+ channels (LTCCs), which contributed to the abnormal neurite extension and sustained activation of cAMP response element binding protein (CREB), a critical mediator of synaptic plasticity. Expression of Cav1.3, a subtype of LTCCs, was increased in TSC2 -/- neurons, but long-term rapamycin treatment suppressed this increase and reversed the altered neuronal activity and neurite extensions. Thus, we identified Cav1.3 LTCC as a critical downstream component of TSC-mTOR signaling that would trigger enhanced neuronal network activity of TSC2 -/- neurons. We suggest that LTCCs could be potential novel targets for the treatment of epilepsy in TSC.SIGNIFICANCE STATEMENT There is a close relationship between elevated mammalian target of rapamycin (mTOR) activity and epilepsy in tuberous sclerosis complex (TSC). However, the underlying mechanism by which mTOR causes epilepsy remains unknown. In this study, using human TSC2 -/- neurons, we identified elevated Ca2+ influx via L-type Ca2+ channels as a critical downstream component of TSC-mTOR signaling and a potential cause of both elevated neuronal activity and neurite extension in TSC2 -/- neurons. Our findings demonstrate a previously unrecognized connection between sustained mTOR activation and elevated Ca2+ signaling via L-type Ca2+ channels in human TSC neurons, which could cause epilepsy in TSC.

Project description:Background and purposeThe calcimimetic, (R)-N-(3-(3-(trifluoromethyl)phenyl)propyl)-1-(1-napthyl)ethylamine hydrochloride (cinacalcet), which activates Ca²(+) -sensing receptors (CaR) in parathyroid glands, is used to treat hyperparathyroidism. Interestingly, CaR in perivascular nerves or endothelial cells is also thought to modulate vascular tone. This study aims to characterize the vascular actions of calcimimetics.Experimental approachIn rat isolated small mesenteric arteries, the relaxant responses to the calcimimetics, cinacalcet and (R)-2-[[[1-(1-naphthyl)ethyl]amino]methyl]-1H-indole hydrochloride (calindol) were characterized, with particular emphasis on the role of CaR, endothelium, perivascular nerves, K(+) channels and Ca²(+) channels. Effects of L-ornithine, which activates a Ca(2+) -sensitive receptor related to CaR (GPRC6A), were also tested.Key resultsCinacalcet induced endothelium-independent relaxation (pEC₅₀ 5.58 ± 0.07, E(max) 97 ± 6%) that was insensitive to sensory nerve desensitization by capsaicin or blockade of large-conductance Ca²(+) -activated K(+) channels by iberiotoxin. Calindol, another calcimimetic, caused more potent relaxation (pEC₅₀ 6.10 ± 0.10, E(max) 101 ± 6%), which was attenuated by endothelial removal or capsaicin, but not iberiotoxin. The negative modulator of CaR, calhex 231 or changes in [Ca²(+) ](o) had negligible effect on relaxation to both calcimimetics. The calcimimetics relaxed vessels precontracted with high [K(+) ](o) and inhibited Ca²(+) influx in endothelium-denuded vessels stimulated by methoxamine, but not ionomycin. They also inhibited contractions to the L-type Ca²(+) channel activator, BayK8644. L-ornithine induced small relaxation alone and had no effect on the responses to calcimimetics.Conclusion and implicationsCinacalcet and calindol are potent arterial relaxants. Under the experimental conditions used, they predominantly act by inhibiting Ca²(+) influx through L-type Ca²(+) channels into vascular smooth muscle, whereas Ca²(+) -sensitive receptors (CaR or GPRC6A) play a minor role.

Dataset Information

PRRT2 modulates presynaptic Ca²⁺ influx by interacting with P/Q-type channels.

Publications

PRRT2 modulates presynaptic Ca<sup>2+</sup> influx by interacting with P/Q-type channels.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets