Proteolytic Processing of the C Terminus of the α1CSubunit of L-type Calcium Channels and the Role of a Proline-rich Domain in Membrane Tethering of Proteolytic Fragments

We identified breast cancer-associated protein (BCA3) as a novel binding partner of Mason-Pfizer monkey virus (MPMV) protease (PR). The interaction was confirmed by co-immunoprecipitation and immunocolocalization of MPMV PR and BCA3. Full-length but not C-terminally truncated BCA3 was incorporated into MPMV virions. We ruled out the potential role of the G-patch domain, a glycine-rich domain located at the C terminus of MPMV PR, in BCA3 interaction and virion incorporation. Expression of BCA3 did not affect MPMV particle release and proteolytic processing; however, it slightly increased MPMV infectivity.

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Proteolytic maturation of α2δ represents a checkpoint for activation and neuronal trafficking of latent calcium channels

eLife ◽

10.7554/elife.21143 ◽

2016 ◽

Vol 5 ◽

Cited By ~ 24

Author(s):

Ivan Kadurin ◽

Laurent Ferron ◽

Simon W Rothwell ◽

James O Meyer ◽

Leon R Douglas ◽

...

Keyword(s):

Calcium Channels ◽

Proteolytic Cleavage ◽

Proteolytic Processing ◽

Calcium Currents ◽

Cleavage Sites ◽

Voltage Dependent ◽

Neuronal Processes ◽

Associated Proteins ◽

Synaptic Boutons

The auxiliary α2δ subunits of voltage-gated calcium channels are extracellular membrane-associated proteins, which are post-translationally cleaved into disulfide-linked polypeptides α2 and δ. We now show, using α2δ constructs containing artificial cleavage sites, that this processing is an essential step permitting voltage-dependent activation of plasma membrane N-type (CaV2.2) calcium channels. Indeed, uncleaved α2δ inhibits native calcium currents in mammalian neurons. By inducing acute cell-surface proteolytic cleavage of α2δ, voltage-dependent activation of channels is promoted, independent from the trafficking role of α2δ. Uncleaved α2δ does not support trafficking of CaV2.2 channel complexes into neuronal processes, and inhibits Ca2+ entry into synaptic boutons, and we can reverse this by controlled intracellular proteolytic cleavage. We propose a model whereby uncleaved α2δ subunits maintain immature calcium channels in an inhibited state. Proteolytic processing of α2δ then permits voltage-dependent activation of the channels, acting as a checkpoint allowing trafficking only of mature calcium channel complexes into neuronal processes.

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Role of the C terminus of the α1C(CaV1.2) Subunit in Membrane Targeting of Cardiac L-type Calcium Channels

Journal of Biological Chemistry ◽

10.1074/jbc.m003465200 ◽

2000 ◽

Vol 275 (33) ◽

pp. 25436-25444 ◽

Cited By ~ 54

Author(s):

Tianyan Gao ◽

Moritz Bünemann ◽

Brian L. Gerhardstein ◽

Hong Ma ◽

M. Marlene Hosey

Keyword(s):

Calcium Channels ◽

Membrane Targeting ◽

C Terminus

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The making of a Lewy body: the role of alpha-synuclein post-fibrillization modifications in regulating the formation and the maturation of pathological inclusions.

10.1101/500058 ◽

2018 ◽

Cited By ~ 14

Author(s):

Anne-Laure Mahul-Mellier ◽

Firat Altay ◽

Johannes Burtscher ◽

Niran Maharjan ◽

Nadine Ait Bouziad ◽

...

Keyword(s):

Lewy Body ◽

Molecular Mechanisms ◽

Alpha Synuclein ◽

Therapeutic Strategies ◽

Proteolytic Processing ◽

Primary Neurons ◽

Cellular Mechanisms ◽

C Terminus ◽

Imaging Approach

Although converging evidence point to alpha-synuclein (a-syn) aggregation and Lewy body (LB) formation as central events in Parkinson's disease (PD), the molecular mechanisms that regulate these processes and their role in disease pathogenesis remain poorly understood. Herein, we applied an integrative biochemical, structural and imaging approach to elucidate the sequence, molecular and cellular mechanisms that regulate LB formation in primary neurons. Our results establish that post-fibrillization C-terminal truncation mediated by calpains 1 and 2 and potentially other enzymes, plays critical roles in regulating a-syn seeding, fibrillization and orchestrates many of the events associated with LB formation and maturation. These findings combined with the abundance of a-syn truncated species in LBs and pathological a-syn aggregates have significant implications for ongoing efforts to develop therapeutic strategies based on targeting the C-terminus of a-syn or proteolytic processing of this region.

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The Cac1 subunit of histone chaperone CAF-1 organizes CAF-1-H3/H4 architecture and tetramerizes histones

eLife ◽

10.7554/elife.18023 ◽

2016 ◽

Vol 5 ◽

Cited By ~ 27

Author(s):

Wallace H Liu ◽

Sarah C Roemer ◽

Yeyun Zhou ◽

Zih-Jie Shen ◽

Briana K Dennehey ◽

...

Keyword(s):

Protein Interactions ◽

Histone Chaperone ◽

Protein Protein Interactions ◽

Rich Domain ◽

C Terminus ◽

Assembly Factor ◽

Hydrogen Deuterium ◽

And Function ◽

Minimal Region

The histone chaperone Chromatin Assembly Factor 1 (CAF-1) deposits tetrameric (H3/H4)2 histones onto newly-synthesized DNA during DNA replication. To understand the mechanism of the tri-subunit CAF-1 complex in this process, we investigated the protein-protein interactions within the CAF-1-H3/H4 architecture using biophysical and biochemical approaches. Hydrogen/deuterium exchange and chemical cross-linking coupled to mass spectrometry reveal interactions that are essential for CAF-1 function in budding yeast, and importantly indicate that the Cac1 subunit functions as a scaffold within the CAF-1-H3/H4 complex. Cac1 alone not only binds H3/H4 with high affinity, but also promotes histone tetramerization independent of the other subunits. Moreover, we identify a minimal region in the C-terminus of Cac1, including the structured winged helix domain and glutamate/aspartate-rich domain, which is sufficient to induce (H3/H4)2 tetramerization. These findings reveal a key role of Cac1 in histone tetramerization, providing a new model for CAF-1-H3/H4 architecture and function during eukaryotic replication.

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Factor Xa Enhances the Binding of Tissue Factor Pathway Inhibitor to Acidic Phospholipids

Thrombosis and Haemostasis ◽

10.1055/s-0038-1650369 ◽

1996 ◽

Vol 75 (05) ◽

pp. 796-800 ◽

Cited By ~ 10

Author(s):

Sanne Valentin ◽

Inger Schousboe

Keyword(s):

Tissue Factor ◽

Tissue Factor Pathway Inhibitor ◽

Factor Xa ◽

Microtitre Plate ◽

C Terminus ◽

Microtitre Plate Assay ◽

Kunitz Domain ◽

Tissue Factor Pathway ◽

Acidic Phospholipids

SummaryIn the present study, the interaction between tissue factor pathway inhibitor (TFPI) and phospholipids has been characterized using a microtitre plate assay. TFPI was shown to bind calcium-independently to an acidic phospholipid surface composed of phosphatidylserine, but not a surface composed of the neutral phosphatidylcholine. The interaction was demonstrated to be dependent on the presence of the TFPI C-terminus. The presence of heparin (1 U/ml, unfractionated) was able to significantly reduce the binding of TFPI to phospholipid. The interaction of TFPI with phosphatidylserine was significantly decreased in the presence of calcium, but this was counteracted, and even enhanced, following complex formation of TFPI with factor Xa prior to incubation with the phospholipid surface. Moreover, a TFPI variant, not containing the third Kunitz domain and the C-terminus, was unable to bind to phospholipid. However, following the formation of a TFPI/factor Xa-complex this TFPI variant was capable of interacting with the phospholipid surface. This indicates that the role of factor Xa as a TFPI cofactor, at least in part, is to mediate the binding of TFPI to the phospholipid surface.

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INTERLEUKIN-6 EXPRESSION IN RAT'S MUSCLE SOLEUS DURING FUNCTIONAL UNLOADING: DYNAMICS OF THE PROCESS AND ROLE OF L-TYPE CALCIUM CHANNELS

Aerospace and Environmental Medicine ◽

10.21687/0233-528x-2020-54-3-70-78 ◽

2020 ◽

pp. 70-78

Author(s):

N.A. Vilchinskaya ◽

◽

I.I. Paramonova ◽

T.L. Nemirovskaya ◽

Yu.N. Lomonosova ◽

...

Keyword(s):

Calcium Channels ◽

Interleukin 6 ◽

Functional Unloading

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A CACNA1A variant associated with trigeminal neuralgia alters the gating of Cav2.1 channels

Molecular Brain ◽

10.1186/s13041-020-00725-y ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Eder Gambeta ◽

Maria A. Gandini ◽

Ivana A. Souza ◽

Laurent Ferron ◽

Gerald W. Zamponi

Keyword(s):

Trigeminal Neuralgia ◽

Missense Mutation ◽

Neurotransmitter Release ◽

Trigeminal System ◽

Wild Type ◽

Calcium Dependent ◽

Whole Cell Patch Clamp ◽

C Terminus ◽

Dependent Inactivation

AbstractA novel missense mutation in the CACNA1A gene that encodes the pore forming α1 subunit of the CaV2.1 voltage-gated calcium channel was identified in a patient with trigeminal neuralgia. This mutation leads to a substitution of proline 2455 by histidine (P2455H) in the distal C-terminus region of the channel. Due to the well characterized role of this channel in neurotransmitter release, our aim was to characterize the biophysical properties of the P2455H variant in heterologously expressed CaV2.1 channels. Whole-cell patch clamp recordings of wild type and mutant CaV2.1 channels expressed in tsA-201 cells reveal that the mutation mediates a depolarizing shift in the voltage-dependence of activation and inactivation. Moreover, the P2455H mutant strongly reduced calcium-dependent inactivation of the channel that is consistent with an overall gain of function. Hence, the P2455H CaV2.1 missense mutation alters the gating properties of the channel, suggesting that associated changes in CaV2.1-dependent synaptic communication in the trigeminal system may contribute to the development of trigeminal neuralgia.

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