Interaction of the Lys3614–Asn3643 calmodulin-binding domain with the Cys4114-Asn4142 region of the type 1 ryanodine receptor is involved in the mechanism of Ca2+/agonist-induced channel activation

2008 ◽  
Vol 411 (2) ◽  
pp. 415-423 ◽  
Author(s):  
Jaya P. Gangopadhyay ◽  
Noriaki Ikemoto

In the present study we show that the interaction of the CaM (calmodulin)-binding domain (Lys3614–Asn3643) with the Cys4114–Asn4142 region (a region included in the CaM-like domain) serves as an intrinsic regulator of the RyR1 (type-1 ryanodine receptor). We tested the effects of antibodies raised against the two putative key regions of RyR1 [anti-(Lys3614–Asn3643) and anti-(Cys4114–Asn4142) antibodies]. Both antibodies produced significant inhibition of [3H]ryanodine-binding activity of RyR1. This suggests that the inter-domain interaction between the two domains, Lys3614–Asn3643 and Cys4114–Asn4142, activates the channel, and that the binding of antibody to either side of the interacting domain pair interfered with the formation of a ‘channel-activation link’ between the two regions. In order to spectroscopically monitor the mode of interaction of these domains, the site of inter-domain interaction was fluorescently labelled with MCA [(7-methoxycoumarin-4-yl)acetyl] in a site-directed manner. The accessibility of the bound MCA to a large molecular mass fluorescence quencher, BSA-QSY (namely, the size of a gap between the interacting domains) decreased with an increase of [Ca2+] in a range of 0.03–2.0 μM, as determined by Stern–Volmer fluorescence quenching analysis. The Ca2+-dependent decrease in the quencher accessibility was more pronounced in the presence of 150 μM 4-CmC (4-chlorometacresol), and was reversed by 1 mM Mg2+ (a well-known inhibitor of Ca2+/agonist-induced channel activation). These results suggest that the Lys3614–Asn3643 and Cys4114–Asn4142 regions of RyR1 interact with each other in a Ca2+- and agonist-dependent manner, and this serves as a mechanism of Ca2+- and agonist-dependent activation of the RyR1 Ca2+ channel.

1991 ◽  
Vol 66 (03) ◽  
pp. 310-314 ◽  
Author(s):  
David C Sane ◽  
Tammy L Moser ◽  
Charles S Greenberg

SummaryVitronectin (VN) stabilizes plasminogen activator inhibitor type 1 (PAI-1) activity and prevents the fibrin(ogen)-induced acceleration of plasminogen activation by t-PA. These antifibrinolytic activities as well as other functions are mediated by the glycosaminoglycan (GAG) binding domain of VN. Since the GAG binding region is rich in arginyl and lysyl residues, it is a potential target for enzymes such as plasmin. In this paper, the dose and time-dependent proteolysis of VN by plasmin is demonstrated. The addition of urokinase or streptokinase (200 units/ml) to plasma also produced proteolysis of VN. With minimal proteolysis, the 75 kDa band was degraded to a 62-65 kDa form of VN. This minimal proteolysis destroyed the binding of [3H]-heparin to VN and reversed the neutralization of heparin by VN.Thus, the plasmin-mediated proteolysis of the GAG binding activity of VN could destroy the antifibrinolytic activity of VN during physiologic conditions and during thrombolytic therapy. Furthermore, other functions of VN in complement and coagulation systems that are mediated by the GAG binding domain may be destroyed by plasmin proteolysis.


2019 ◽  
Vol 170 (2) ◽  
pp. 509-524
Author(s):  
Kim M Truong ◽  
Gennady Cherednichenko ◽  
Isaac N Pessah

Abstract Dichlorodiphenyltrichloroethane (DDT) and its metabolite dichlorodiphenyldichloroethylene (DDE) are ubiquitous in the environment and detected in tissues of living organisms. Although DDT owes its insecticidal activity to impeding closure of voltage-gated sodium channels, it mediates toxicity in mammals by acting as an endocrine disruptor (ED). Numerous studies demonstrate DDT/DDE to be EDs, but studies examining muscle-specific effects mediated by nonhormonal receptors in mammals are lacking. Therefore, we investigated whether o,p′-DDT, p,p′-DDT, o,p′-DDE, and p,p′-DDE (DDx, collectively) alter the function of ryanodine receptor type 1 (RyR1), a protein critical for skeletal muscle excitation-contraction coupling and muscle health. DDx (0.01–10 µM) elicited concentration-dependent increases in [3H]ryanodine ([3H]Ry) binding to RyR1 with o,p′-DDE showing highest potency and efficacy. DDx also showed sex differences in [3H]Ry-binding efficacy toward RyR1, where [3H]Ry-binding in female muscle preparations was greater than male counterparts. Measurements of Ca2+ transport across sarcoplasmic reticulum (SR) membrane vesicles further confirmed DDx can selectively engage with RyR1 to cause Ca2+ efflux from SR stores. DDx also disrupts RyR1-signaling in HEK293T cells stably expressing RyR1 (HEK-RyR1). Pretreatment with DDx (0.1–10 µM) for 100 s, 12 h, or 24 h significantly sensitized Ca2+-efflux triggered by RyR agonist caffeine in a concentration-dependent manner. o,p′-DDE (24 h; 1 µM) significantly increased Ca2+-transient amplitude from electrically stimulated mouse myotubes compared with control and displayed abnormal fatigability. In conclusion, our study demonstrates DDx can directly interact and modulate RyR1 conformation, thereby altering SR Ca2+-dynamics and sensitize RyR1-expressing cells to RyR1 activators, which may ultimately contribute to long-term impairments in muscle health.


2009 ◽  
Vol 77 (11) ◽  
pp. 5130-5138 ◽  
Author(s):  
Hideki Nagata ◽  
Mio Iwasaki ◽  
Kazuhiko Maeda ◽  
Masae Kuboniwa ◽  
Ei Hashino ◽  
...  

ABSTRACT Porphyromonas gingivalis forms communities with antecedent oral biofilm constituent streptococci. P. gingivalis major fimbriae bind to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) present on the streptococcal surface, and this interaction plays an important role in P. gingivalis colonization. This study identified the binding domain of Streptococcus oralis GAPDH for P. gingivalis fimbriae. S. oralis recombinant GAPDH (rGAPDH) was digested with lysyl endopeptidase. Cleaved fragments of rGAPDH were applied to a reverse-phase high-pressure liquid chromatograph equipped with a C18 column. Each peak was collected; the binding activity toward P. gingivalis recombinant fimbrillin (rFimA) was analyzed with a biomolecular interaction analysis system. The fragment displaying the strongest binding activity was further digested with various proteinases, after which the binding activity of each fragment was measured. The amino acid sequence of each fragment was determined by direct sequencing, mass spectrometric analysis, and amino acid analysis. Amino acid residues 166 to 183 of S. oralis GAPDH exhibited the strongest binding activity toward rFimA; confocal laser scanning microscopy revealed that the synthetic peptide corresponding to amino acid residues 166 to 183 of S. oralis GAPDH (pep166-183, DNFGVVEGLMTTIHAYTG) inhibits S. oralis-P. gingivalis biofilm formation in a dose-dependent manner. Moreover, pep166-183 inhibited interbacterial biofilm formation by several oral streptococci and P. gingivalis strains with different types of FimA. These results indicate that the binding domain of S. oralis GAPDH for P. gingivalis fimbriae exists within the region encompassing amino acid residues 166 to 183 of GAPDH and that pep166-183 may be a potent inhibitor of P. gingivalis colonization in the oral cavity.


2019 ◽  
Vol 476 (2) ◽  
pp. 193-209 ◽  
Author(s):  
Malene Brohus ◽  
Mads T. Søndergaard ◽  
Sui Rong Wayne Chen ◽  
Filip van Petegem ◽  
Michael T. Overgaard

Abstract The Ca2+ sensor calmodulin (CaM) regulates cardiac ryanodine receptor (RyR2)-mediated Ca2+ release from the sarcoplasmic reticulum. CaM inhibits RyR2 in a Ca2+-dependent manner and aberrant CaM-dependent inhibition results in life-threatening cardiac arrhythmias. However, the molecular details of the CaM–RyR2 interaction remain unclear. Four CaM-binding domains (CaMBD1a, -1b, -2, and -3) in RyR2 have been proposed. Here, we investigated the Ca2+-dependent interactions between CaM and these CaMBDs by monitoring changes in the fluorescence anisotropy of carboxytetramethylrhodamine (TAMRA)-labeled CaMBD peptides during titration with CaM at a wide range of Ca2+ concentrations. We showed that CaM bound to all four CaMBDs with affinities that increased with Ca2+ concentration. CaM bound to CaMBD2 and -3 with high affinities across all Ca2+ concentrations tested, but bound to CaMBD1a and -1b only at Ca2+ concentrations above 0.2 µM. Binding experiments using individual CaM domains revealed that the CaM C-domain preferentially bound to CaMBD2, and the N-domain to CaMBD3. Moreover, the Ca2+ affinity of the CaM C-domain in complex with CaMBD2 or -3 was so high that these complexes are essentially Ca2+ saturated under resting Ca2+ conditions. Conversely, the N-domain senses Ca2+ exactly in the transition from resting to activating Ca2+ when complexed to either CaMBD2 or -3. Altogether, our results support a binding model where the CaM C-domain is anchored to RyR2 CaMBD2 and saturated with Ca2+ during Ca2+ oscillations, while the CaM N-domain functions as a dynamic Ca2+ sensor that can bridge noncontiguous regions of RyR2 or clamp down onto CaMBD2.


2006 ◽  
Vol 401 (1) ◽  
pp. 317-324 ◽  
Author(s):  
Takashi Kimura ◽  
Suzy M. Pace ◽  
Lan Wei ◽  
Nicole A. Beard ◽  
Robert T. Dirksen ◽  
...  

The aim of the present study was to examine residues that are variably spliced in the juvenile and adult isoforms of the skeletal-muscle RyR1 (type 1 ryanodine receptor). The juvenile ASI(−) splice variant is less active than the adult ASI(+) variant and is overexpressed in patients with DM (myotonic dystrophy) [Kimura, Nakamori, Lueck, Pouliquin, Aoike, Fujimura, Dirksen, Takahashi, Dulhunty and Sakoda (2005) Hum. Mol. Genet. 14, 2189–2200]. In the present study, we explore the ASI region using synthetic peptides corresponding to rabbit RyR1 residues Thr3471-Gly3500 either containing [PASI(+)] or lacking [PASI(−)] the ASI residues. Both peptides increased [3H]ryanodine binding to rabbit RyR1s, increased Ca2+ release from sarcoplasmic reti-culum vesicles and increased single RyR1 channel activity. The peptide PASI(−) was more active in each case than PASI(+). [3H]Ryanodine binding to recombinant ASI(+)RyR1 or ASI(−)-RyR1 was enhanced more by PASI(−) than PASI(+), with the greatest increase seen when PASI(−) was added to ASI(−)RyR1. The activation of the RyR channels is consistent with the hypo-thesis that the peptides interrupt an inhibitory inter-domain inter-action and that PASI(−) is more effective at interrupting this interaction than PASI(+). We therefore suggest that the ASI(−) sequence interacts more tightly than the ASI(+) sequence with its binding partner, so that the ASI(−)RyR1 is more strongly inhibited (less active) than the ASI(+)RyR1. Thus the affinity of the binding partners in this inter-domain interaction may deter-mine the activities of the mature and juvenile isoforms of RyR1 and the stronger inhibition in the juvenile isoform may contribute to the myopathy in DM.


1996 ◽  
Vol 316 (1) ◽  
pp. 295-302 ◽  
Author(s):  
Md. Omedul ISLAM ◽  
Yutaka YOSHIDA ◽  
Takaki KOGA ◽  
Masayasu KOJIMA ◽  
Kenji KANGAWA ◽  
...  

myo-Inositol 1,4,5-trisphosphate (InsP3) receptor of porcine aorta was purified to near homogeneity and its biochemical properties were compared with those of cerebellar InsP3 receptor of the same animal species. The aortic InsP3 receptor consisted of equal amounts of two polypeptides with slightly differing molecular masses of around 240 kDa and was found to possess a single population of InsP3-binding site (Kd of 1.2 nM). The InsP3 receptor purified from porcine cerebellum was also comprised of two polypeptides. However, the molecular mass was slightly but definitely larger, being 250 kDa, and the amounts of the two polypeptides were not equal. The aortic InsP3 receptor cross-reacted with polyclonal antibody specific to type 1 InsP3 receptor as did the cerebellar InsP3 receptor. The aortic InsP3 receptor bound to calmodulin–Sepharose in a Ca2+-dependent manner, while the cerebellar InsP3 receptor did not. Reverse transcriptase-PCR analysis revealed two splicing variants of the type 1 InsP3 receptor in porcine aortic smooth muscle distinct from those of the type 1 InsP3 receptor of porcine cerebellum. The possible relevance of this difference to difference in calmodulin-binding property was discussed.


1995 ◽  
Vol 308 (1) ◽  
pp. 83-88 ◽  
Author(s):  
M Yamada ◽  
A Miyawaki ◽  
K Saito ◽  
T Nakajima ◽  
M Yamamoto-Hino ◽  
...  

We determined the amino acid sequence responsible for the calmodulin (CaM)-binding ability of mouse type 1 Ins(1,4,5)P3 receptor (IP3R1). We expressed various parts of IP3R1 from deleted cDNA and examined their CaM-binding ability. It was shown that the sequence stretching from Lys-1564 to Arg-1585 is necessary for the binding. The full-length IP3R1 with replacement of Trp-1576 by Ala lost its CaM-binding ability. Antibody against residues 1564-1585 of IP3R1 inhibited cerebellar IP3R1 from binding CaM. The fluorescence spectrum of the peptide that corresponds to residues 1564-1585 shifted when Ca(2+)-CaM was added. From the change in the fluorescence spectrum, we estimated the dissociation constant (KD) between the peptide and CaM to be 0.7 microM. The submicromolar value of KD suggests an actual interaction between CaM and IP3R1 within cells. The CaM-binding ability of other types of IP3Rs was also examined. A part of the type 2IP3R, including the region showing sequence identity with the CaM-binding domain of IP3R1, also bound CaM, while the expressed full-length type 3 IP3R did not.


2011 ◽  
Vol 438 (2) ◽  
pp. 379-387 ◽  
Author(s):  
Jaya P. Gangopadhyay ◽  
Noriaki Ikemoto

We have shown previously that the inter-domain interaction between the two domains of RyR (ryanodine receptor), CaMBD [CaM (calmodulin)-binding domain] and CaMLD (CaM-like domain), activates the Ca2+ channel, and this process is called activation-link formation [Gangopadhyay and Ikemoto (2008) Biochem. J. 411, 415–423]. Thus CaM that is bound to CaMBD is expected to interfere the activation-link formation, thereby stabilizing the closed state of the channel under normal conditions. In the present paper, we report that, upon stimulation of neonatal cardiomyocytes with the pro-hypertrophy agonist ET-1 (endothelin-1), CaM dissociates from the RyR, which induces a series of intracellular events: increased frequency of Ca2+ transients, translocation of the signalling molecules CaM, CaMKII (CaM kinase II) and the transcription factor NFAT (nuclear factor of activated T-cells) to the nucleus. These events then lead to the development of hypertrophy. Importantly, an anti-CaMBD antibody that interferes with activation-link formation prevented all of these intracellular events triggered by ET-1 and prevented the development of hypertrophy. These results indicate that the aberrant formation of the activation link between CaMBD and CaMLD of RyR is a key step in the development of hypertrophy in cultured cardiomyocytes.


1998 ◽  
Vol 330 (3) ◽  
pp. 1461-1467 ◽  
Author(s):  
Kari KEINÄNEN ◽  
Annukka JOUPPILA ◽  
Arja KUUSINEN

Recombinant fragments of the kainate-selective glutamate recep-tor subunit GluR-6 were expressed in insect cells and analysed for [3H]kainate binding activity in order to characterize the structural determinants responsible for ligand recognition. Deletion of the N-terminal ~ 400 amino-acid-residue segment and the C-terminal ~ 90 residues resulted in a membrane-bound core fragment which displayed pharmacologically native-like [3H]kainate binding properties. Further replacement of the membrane-embedded segments M1-M3 by a hydrophilic linker peptide gave rise to a soluble polypeptide which was accumulated in the culture medium. When bound to chelating Sepharose beads via a C-terminal histidine tag, the soluble fragment showed low-affinity binding of [3H]kainate, which was displaced in a concentration-dependent manner by unlabelled domoic acid, L-glutamate and 6-cyano-7-nitroquinoxaline-2,3-dione. Our results indicate that the kainate-binding site is formed exclusively by the two discontinuous extracellular segments (S1 and S2) which are homologous to bacterial amino-acid-binding proteins. Ligand binding characteristics of soluble S1-S2 chimaeras between the GluR-6 and GluR-D subunits showed that, whereas both S1 and S2 segments contribute to agonist-selectivity, the N-terminal one-third of the GluR-D S2 segment is sufficient to confer α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate-binding capacity to the chimaeric ligand-binding domain.


2013 ◽  
Vol 126 (19) ◽  
pp. 4527-4535 ◽  
Author(s):  
X. Huang ◽  
Y. Liu ◽  
R. Wang ◽  
X. Zhong ◽  
Y. Liu ◽  
...  

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