Interaction of Cysteine String Proteins with the α1A Subunit of the P/Q-type Calcium Channel

Lévêque, Christian; Pupier, Sandrine; Marqueze, B; Geslin, Lionel; Kataoka, Masakazu; Takahashi, Masami; Waard, Michel De; Seagar, Michael

doi:10.1074/jbc.273.22.13488

Cited by 94 publications

(82 citation statements)

References 34 publications

(44 reference statements)

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“…Instead, in the absence of CSP␣, the calyx synapse developed an age-dependent functional impairment, consistent with a role for CSP␣ as part of a molecular chaperone that makes it possible for synapses to keep running for extended time periods (2). Although this hypothesis was in agreement with previous observations in CSP-deficient flies (4), alternative hypotheses about the function of CSP were proposed based on the phenotype of CSP-deficient flies and on biochemical studies of protein-protein interactions mediated by CSP (7)(8)(9)(10)(11)(12)(13)(14).…”

supporting

confidence: 72%

CSPα-deficiency causes massive and rapid photoreceptor degeneration

Schmitz

Tabares²,

Khimich³

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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Cysteine string protein (CSP) ␣ is an abundant synaptic vesicle protein that contains a DNA-J domain characteristic of Hsp40-type cochaperones. Previous studies showed that deletion of CSP␣ in mice leads to massive lethal neurodegeneration but did not clarify how the neurodegeneration affects specific subpopulations of neurons. Here, we analyzed the effects of the CSP␣ deficiency on tonically active ribbon synapses of the retina and the inner ear. We show that CSP␣-deficient photoreceptor terminals undergo dramatic and rapidly progressive neurodegeneration that starts before eye opening and initially does not affect other retinal synapses. These changes are associated with progressive blindness. In contrast, ribbon synapses of auditory hair cells did not exhibit presynaptic impairments in CSP␣-deficient mice. Hair cells, but not photoreceptor cells or central neurons, express CSP␤, thereby accounting for the lack of a hair-cell phenotype in CSP␣ knockout mice. Our data demonstrate that tonically active ribbon synapses in retina are particularly sensitive to the deletion of CSP␣ and that expression of at least one CSP isoform is essential to protect such tonically active synapses from neurodegeneration.hair cell ͉ ribbon synapse ͉ electroretinogram ͉ chaperone ͉ blindness S ynaptic vesicle exo-and endocytosis is mediated by a sophisticated machinery that allows nerve terminals to operate at high speed (1). Such continuous membrane traffic requires specific mechanisms to deal with the use-dependent aging and denaturation of proteins. One such mechanism may involve the synaptic vesicle protein cysteine string protein (CSP) ␣ that is thought to function as a cochaperone in presynaptic terminals (2, 3).CSP␣ is an abundant presynaptic protein (4) that contains a string of cysteine residues and a DNA-J domain that functionally collaborates with the DNA-K domains of Hsc70 proteins (reviewed in refs. 5 and 6). CSP␣ activates the ATPase activity of Hsc70 (7,8) and forms a trimeric complex with Hsc70 and the tetratricopeptide repeat protein SGT (3). This complex catalyzes the ATP-dependent refolding of denatured luciferase (3). Invertebrates have a single CSP gene, whereas mammals express three CSP genes: CSP␣ that is widely distributed but highly enriched in brain, and CSP␤ and CSP␥ that are primarily found in testis (2).Analyses of knockout (KO) mice revealed that CSP␣-deficient mice are relatively normal at birth but exhibit a progressive lethal phenotype that results in death after 2-4 months (2). Recordings in the Calyx of Held synapse of CSP␣ KO mice documented that CSP␣ is not required for N-, P͞Q-, and R-type Ca 2ϩ -channel function or Ca 2ϩ -triggered vesicle exocytosis. Instead, in the absence of CSP␣, the calyx synapse developed an age-dependent functional impairment, consistent with a role for CSP␣ as part of a molecular chaperone that makes it possible for synapses to keep running for extended time periods (2). Although this hypothesis was in agreement with previous observations in CSP-deficient flies (4), alt...

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supporting

confidence: 72%

CSPα-deficiency causes massive and rapid photoreceptor degeneration

Schmitz

Tabares²,

Khimich³

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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“…It was also suggested that the signal necessary for correct plasma membrane targeting of Lc-type calcium channel complexes is generated as a result of a functional interaction between the ␣ 1 and ␤ subunits (21,48). Here we showed that Sx1A inhibition is strongly affected by the channel subunit composition.…”

Section: Figmentioning

confidence: 48%

“…Co-expression of ␣ 2 ␦ (either with or without ␤) triples the channel density on the cell membrane, whereas expression of ␤2a increases the open state probability (P o ) (14). The ␣ 1 subunit contains binding sites for pharmacological agents, proteins, or toxins and determines the electrophysiological properties of different types of Ca 2ϩ channels (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25) as well as interaction sites with Sx1A, SNAP-25, and synaptotagmin (26 -34). The II-III linker of the ␣ 1 subunit was suggested to be the docking site of exocytotic vesicles (13, 29 -31, 34).…”

mentioning

confidence: 99%

Syntaxin 1A Modulates the Voltage-gated L-type Calcium Channel (Cav1.2) in a Cooperative Manner

Arien¹,

Wiser²,

Arkin

et al. 2003

Journal of Biological Chemistry

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Syntaxin 1A (Sx1A) modifies the activity of voltagegated Ca 2؉ channels acting via the cytosolic and the two vicinal cysteines (271 and 272) at the transmembrane domain. Here we show that Sx1A modulates the Lc-type Ca 2؉ channel, Ca v 1.2, in a cooperative manner, and we explore whether channel clustering or the Sx1A homodimer is responsible for this activity. Sx1A formed homodimers but, when mutated at the two vicinal transmembrane domain cysteines, was unable to either dimerize or modify the channel activity suggesting disulfide bond formation. Moreover, applying global molecular dynamic search established a theoretical prospect of generating a disulfide bond between two Sx1A transmembrane helices. Nevertheless, Sx1A activity was not correlated with Sx1A homodimer. Application of a vicinal thiol reagent, phenylarsine oxide, abolished Sx1A action indicating the accessibility of Cys-271,272 thiols. Sx1A inhibition of channel activity was restored by phenylarsine oxide antidote, 2,3-dimercaptopropanol, consistent with thiol interaction of Sx1A. In addition, the supralinear mode of channel inhibition was correlated to the monomeric form of Sx1A and was apparent only when the three channel subunits ␣ 1 1.2/␣ 2 ␦1/ ␤2a were present. This functional demonstration of cooperativity suggests that the three-subunit channel responds as a cluster, and Sx1A monomers associate with a dimer (or more) of a three-subunit Ca 2؉ channel. Consistent with channel cluster linked to Sx1A, a conformational change driven by membrane depolarization and Ca 2؉ entry would rapidly be transduced to the exocytotic machinery. As shown herein, the supralinear relationship between Sx1A and the voltage-gated Ca 2؉ channel within the cluster could convey the cooperativity that distinguishes the process of neurotransmitter release.Signal transduction in the synapse is initiated by neurotransmitter release as a consequence of fusion that takes place between synaptic vesicles and the plasma membrane. It is commonly accepted that at the heart of this tightly regulated, multifarious process lies the ternary complex formed by the synaptic proteins syntaxin 1A (Sx1A), 1 SNAP-25, and synaptobrevin II (1-3). This ternary complex is thought to be responsible for juxtaposing the synaptic vesicle and the plasma membrane prior to membrane fusion, which involves the binding of soluble N-ethylmaleimide-sensitive factor (NSF) (1-3). It is for this reason that the above-mentioned ternary complex is referred to as the SNARE (receptor for soluble NSF attachment proteins) complex.Analysis of ternary complexes formed by the full-length proteins revealed that the C-terminal transmembrane domains (TMDs) of both Sx1A and synaptobrevin II were protected from trypsin digestion (4). Moreover, inclusion of these TMDs increased the stability of the ternary complexes and affected the ability of the cytoplasmic domains to join other proteins (4, 5). Co-reconstituted into liposomes, synaptobrevin II and syntaxin 1A formed a stable binary complex that required the presence of th...

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“…As observed for other chaperone proteins (29), the HPD motif of the Csp J-domain mediates its binding to and activation of the Hsc70 chaperone ATPases, which influence protein conformation/binding. Structural predictions indicate that the C terminus of Csp1 may form a coiled-coil region, and this structure may be important in view of the emerging evidence that Csp can interact with proteins involved in exocytosis, such as vesicle-associated membrane protein and syntaxins 1A and 4 (21,30,31). Thus, prior results suggest that Csp could link functions of the SNARE complex with those of Hsc70.…”

mentioning

confidence: 99%

Cysteine String Protein Interacts with and Modulates the Maturation of the Cystic Fibrosis Transmembrane Conductance Regulator

Zhang

Peters

Sun

et al. 2002

Journal of Biological Chemistry

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The cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-regulated chloride channel whose phosphorylation regulates both channel gating and its trafficking at the plasma membrane. Cysteine string proteins (Csps) are J-domain-containing, membrane-associated proteins that have been functionally implicated in regulated exocytosis. Therefore, we evaluated the possibility that Csp is involved in regulated CFTR trafficking. We found Csp expressed in mammalian epithelial cell lines, several of which express CFTR. In Calu-3 airway cells, immunofluorescence colocalized Csp with calnexin in the endoplasmic reticulum and with CFTR at the apical membrane domain. CFTR coprecipitated with Csp from Calu-3 cell lysates. Csp associated with both core-glycosylated immature and fully glycosylated mature CFTRs (bands B and C); however, in relation to the endogenous levels of the B and C bands expressed in Calu-3 cells, the Csp interaction with band B predominated. In vitro protein binding assays detected physical interactions of both mammalian Csp isoforms with the CFTR R-domain and the N terminus, having submicromolar affinities. In Xenopus oocytes expressing CFTR, Csp overexpression decreased the chloride current and membrane capacitance increases evoked by cAMP stimulation and decreased the levels of CFTR protein detected by immunoblot. In mammalian cells, the steady-state expression of CFTR band C was eliminated, and pulse-chase studies showed that Csp coexpression blocked the conversion of immature to mature CFTR and stabilized band B. These results demonstrate a primary role for Csp in CFTR protein maturation. The physical interaction of this Hsc70-binding protein with immature CFTR, its localization in the endoplasmic reticulum, and the decrease in production of mature CFTR observed during Csp overexpression reflect a role for Csp in CFTR biogenesis. The documented role of Csp in regulated exocytosis, its interaction with mature CFTR, and its coexpression with CFTR at the apical membrane domain of epithelial cells may reflect also a role for Csp in regulated CFTR trafficking at the plasma membrane.

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Interaction of Cysteine String Proteins with the α1A Subunit of the P/Q-type Calcium Channel

Cited by 94 publications

References 34 publications

CSPα-deficiency causes massive and rapid photoreceptor degeneration

CSPα-deficiency causes massive and rapid photoreceptor degeneration

Syntaxin 1A Modulates the Voltage-gated L-type Calcium Channel (Cav1.2) in a Cooperative Manner

Cysteine String Protein Interacts with and Modulates the Maturation of the Cystic Fibrosis Transmembrane Conductance Regulator

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