Complex formation dynamics of native and mutated pyrin's B30.2 domain with caspase-1

2018 ◽  
Vol 86 (6) ◽  
pp. 676-683 ◽  
Author(s):  
Grigor Arakelov ◽  
Vahram Arakelov ◽  
Karen Nazaryan
Keyword(s):  
Complex Formation ◽  
Caspase 1 ◽  
Formation Dynamics ◽  
B30.2 Domain

scholarly journals The familial Mediterranean fever protein, pyrin, is cleaved by caspase-1 and activates NF-κB through its N-terminal fragment

Blood ◽  
2008 ◽  
Vol 112 (5) ◽  
pp. 1794-1803 ◽  
Author(s):  
Jae Jin Chae ◽  
Geryl Wood ◽  
Katharina Richard ◽  
Howard Jaffe ◽  
Nona T. Colburn ◽  
...  
Keyword(s):  
Familial Mediterranean Fever ◽  
Degradation Products ◽  
Adapter Protein ◽  
Caspase 1 ◽  
Terminal Fragment ◽  
Acid Protein ◽  
Mediterranean Fever ◽  
A Site ◽  
B30.2 Domain ◽  
Amino Acid Protein

Abstract Familial Mediterranean fever (FMF) is an autoinflammatory disease caused by mutations in MEFV, which encodes a 781–amino acid protein denoted pyrin. We have previously shown that pyrin regulates caspase-1 activation and IL-1β production through interaction of its N-terminal PYD motif with the ASC adapter protein, and also modulates IL-1β production by interaction of its C-terminal B30.2 domain with the catalytic domains of caspase-1. We now asked whether pyrin might itself be a caspase-1 substrate, and found that pyrin is cleaved by caspase-1 at Asp330, a site remote from the B30.2 domain. Pyrin variants harboring FMF-associated B30.2 mutations were cleaved more efficiently than wild-type pyrin. The N-terminal cleaved fragment interacted with the p65 subunit of NF-κB and with IκB-α through its 15-aa bZIP basic domain and adjacent sequences, respectively, and translocated to the nucleus. The interaction of the N-terminal fragment with p65 enhanced entrance of p65 into the nucleus. The interaction of N-terminal pyrin with IκB-α induced calpain-mediated degradation of IκB-α, thus potentiating NF-κB activation. Absolute and relative quantities of cleaved pyrin and IκB-α degradation products were substantially increased in leukocytes from FMF patients compared with healthy controls. Our data support a new pyrin/caspase-1 pathway for NF-κB activation.

Comparative Labelling and Biokinetic Studies of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn)

1977 ◽  
Vol 16 (01) ◽  
pp. 30-35 ◽  
Author(s):  
N. Agha ◽  
R. B. R. Persson
Keyword(s):  
Complex Formation ◽  
Significant Influence ◽  
Room Temperature ◽  
Ph Value ◽  
Maximum Activity ◽  
Reduction Step ◽  
Labelling Yield ◽  
Different Temperatures ◽  
Kinetics Of

SummaryGelchromatography column scanning has been used to study the fractions of 99mTc-pertechnetate, 99mTcchelate and reduced hydrolyzed 99mTc in preparations of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn). The labelling yield of 99mTc-EDTA(Sn) chelate was as high as 90—95% when 100 μmol EDTA · H4 and 0.5 (Amol SnCl2 was incubated with 10 ml 99mTceluate for 30—60 min at room temperature. The study of the influence of the pH-value on the fraction of 99mTc-EDTA shows that pH 2.8—2.9 gave the best labelling yield. In a comparative study of the labelling kinetics of 99mTc-EDTA(Sn) and 99mTc- DTPA(Sn) at different temperatures (7, 22 and 37°C), no significant influence on the reduction step was found. The rate constant for complex formation, however, increased more rapidly with increased temperature for 99mTc-DTPA(Sn). At room temperature only a few minutes was required to achieve a high labelling yield with 99mTc-DTPA(Sn) whereas about 60 min was required for 99mTc-EDTA(Sn). Comparative biokinetic studies in rabbits showed that the maximum activity in kidneys is achieved after 12 min with 99mTc-EDTA(Sn) but already after 6 min with 99mTc-DTPA(Sn). The long-term disappearance of 99mTc-DTPA(Sn) from the kidneys is about five times faster than that for 99mTc-EDTA(Sn).

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