scholarly journals Coexistence of Closed and Open Conformations of Complement Factor B in the Alternative Pathway C3bB(Mg2+) Proconvertase

2009 ◽  
Vol 183 (11) ◽  
pp. 7347-7351 ◽  
Author(s):  
Eva Torreira ◽  
Agustín Tortajada ◽  
Tamara Montes ◽  
Santiago Rodríguez de Córdoba ◽  
Oscar Llorca
2021 ◽  
Vol 22 (17) ◽  
pp. 9580
Author(s):  
Hannah Murray ◽  
Beiying Qiu ◽  
Sze Yuan Ho ◽  
Xiaomeng Wang

Complement factor B (CFB), a 95-kDa protein, is a crucial catalytic element of the alternative pathway (AP) of complement. After binding of CFB to C3b, activation of the AP depends on the proteolytic cleavage of CFB by factor D to generate the C3 convertase (C3bBb). The C3 convertase contains the catalytic subunit of CFB (Bb), the enzymatic site for the cleavage of a new molecule of C3 into C3b. In addition to its role in activating the AP, CFB has been implicated in pathological ocular neovascularization, a common feature of several blinding eye diseases, however, with somewhat conflicting results. The focus of this study was to investigate the direct impact of CFB on ocular neovascularization in a tightly controlled environment. Using mouse models of laser-induced choroidal neovascularization (CNV) and oxygen-induced retinopathy (OIR), our study demonstrated an increase in CFB expression during pathological angiogenesis. Results from several in vitro and ex vivo functionality assays indicated a promoting effect of CFB in angiogenesis. Mechanistically, CFB exerts this pro-angiogenic effect by mediating the vascular endothelial growth factor (VEGF) signaling pathway. In summary, we demonstrate compelling evidence for the role of CFB in driving ocular angiogenesis in a VEGF-dependent manner. This work provides a framework for a more in-depth exploration of CFB-mediated effects in ocular angiogenesis in the future.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Long H. Ngo ◽  
M. Austin Argentieri ◽  
Simon T. Dillon ◽  
Blake Victor Kent ◽  
Alka M. Kanaya ◽  
...  

AbstractBlood protein concentrations are clinically useful, predictive biomarkers of cardiovascular disease (CVD). Despite a higher burden of CVD among U.S. South Asians, no CVD-related proteomics study has been conducted in this sub-population. The aim of this study is to investigate the associations between plasma protein levels and CVD incidence, and to assess the potential influence of religiosity/spirituality (R/S) on significant protein-CVD associations, in South Asians from the MASALA Study. We used a nested case–control design of 50 participants with incident CVD and 50 sex- and age-matched controls. Plasma samples were analyzed by SOMAscan for expression of 1305 proteins. Multivariable logistic regression models and model selection using Akaike Information Criteria were performed on the proteins and clinical covariates, with further effect modification analyses conducted to assess the influence of R/S measures on significant associations between proteins and incident CVD events. We identified 36 proteins that were significantly expressed differentially among CVD cases compared to matched controls. These proteins are involved in immune cell recruitment, atherosclerosis, endothelial cell differentiation, and vascularization. A final multivariable model found three proteins (Contactin-5 [CNTN5], Low affinity immunoglobulin gamma Fc region receptor II-a [FCGR2A], and Complement factor B [CFB]) associated with incident CVD after adjustment for diabetes (AUC = 0.82). Religious struggles that exacerbate the adverse impact of stressful life events, significantly modified the effect of Contactin-5 and Complement factor B on risk of CVD. Our research is this first assessment of the relationship between protein concentrations and risk of CVD in a South Asian sample. Further research is needed to understand patterns of proteomic profiles across diverse ethnic communities, and the influence of resources for resiliency on proteomic signatures and ultimately, risk of CVD.


1986 ◽  
Vol 261 (24) ◽  
pp. 11038-11044 ◽  
Author(s):  
P Hensley ◽  
M C O'Keefe ◽  
C J Spangler ◽  
J C Osborne ◽  
C W Vogel

2015 ◽  
Vol 65 (3) ◽  
pp. 520-521 ◽  
Author(s):  
Sanjeev Sethi ◽  
Richard J.H. Smith ◽  
John J. Dillon ◽  
Fernando C. Fervenza

2012 ◽  
Vol 176 (5) ◽  
pp. 361-372 ◽  
Author(s):  
Ammarin Thakkinstian ◽  
Mark McEvoy ◽  
Usha Chakravarthy ◽  
Subhabrata Chakrabarti ◽  
Gareth J. McKay ◽  
...  

1978 ◽  
Vol 171 (1) ◽  
pp. 99-107 ◽  
Author(s):  
M A Kerr ◽  
R R Porter

The second component of human complement (C2) was purified by a combination of euglobulin precipitation, ion-exchange chromatography, (NH4)2SO4 precipitation and affinity chromatography. The final product was homogeneous by the criterion of polyacrylamide-gel electrophoresis and represents a purification of about 4000-fold from serum with 15-20% yield. Component C2 comprises a single carbohydrate-containing polypeptide chain, with an apparent mol.wt. of 102000; alanine is the N-terminal amino acid. The molecule is rapidly cleaved by activated subcomponent C1s with the loss of haemolytic activity to yield two fragments with apparent mol.wts. of 74000 and 34000. These fragments are not linked by disulphide bonds and can be easily separated. A second protein isolated during the purification of component C2 was identified by its haemolytic and antigenic properties as complement Factor B, the protein serving an analogous function to component C2 in the alternative pathway. The protein, which is also a single carbohydrate-containing polypeptide chain, has an apparent mol.wt. of 95000 and threonine as N-terminal amino acid. The amino acid analyses of component C2 and Factor B are compared.


2013 ◽  
Vol 27 (S1) ◽  
Author(s):  
Lin Zou ◽  
Yan Li ◽  
Yan Feng ◽  
Ming Zhang ◽  
Chan Chen ◽  
...  

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