Δ 469 mutation in the type 3 repeat calcium binding domain of cartilage oligomeric matrix protein (COMP) disrupts calcium binding

Cell Calcium ◽  
2000 ◽  
Vol 27 (6) ◽  
pp. 309-314 ◽  
Author(s):  
J. Hou ◽  
J.A. Putkey ◽  
J.T. Hecht
2004 ◽  
Vol 377 (2) ◽  
pp. 479-487 ◽  
Author(s):  
Luitgard SPITZNAGEL ◽  
D. Patric NITSCHE ◽  
Mats PAULSSON ◽  
Patrik MAURER ◽  
Frank ZAUCKE

We have introduced a pseudoachondroplasia-associated mutation (His587→Arg) into the C-terminal collagen-binding domain of COMP (cartilage oligomeric matrix protein) and recombinantly expressed the full-length protein as well as truncated fragments in HEK-293 cells. CD spectroscopy revealed only subtle differences in the overall secondary structure of full-length proteins. Interestingly, the mutant COMP did not aggregate in the presence of calcium, as does the wild-type protein. The binding site for collagens was recently mapped to amino acids 579–595 and it was assumed that the His587→Arg mutation influences collagen binding. However full-length mutant COMP bound to collagens I, II and IX, and the binding was not significantly different from that of wild-type COMP. Also a COMP His587→Arg fragment encompassing the calcium-binding repeats and the C-terminal collagen-binding domain bound collagens equally well as the corresponding wild-type protein. The recombinant fragments encompassing the C-terminal domain alone showed multiple bands following SDS/PAGE, although their theoretical molecular masses could be verified by MS. A temperature-induced conformational change was observed in CD spectroscopy, and negative-staining electron microscopy demonstrated that both wild-type and mutant proteins formed defined elongated aggregates after heating to 60 °C. Our results suggest that the His587→Arg mutation is not itself deleterious to the structure and collagen-binding of COMP.


2020 ◽  
Vol 22 (1) ◽  
pp. 111
Author(s):  
Oksana M. Subach ◽  
Natalia V. Barykina ◽  
Elizaveta S. Chefanova ◽  
Anna V. Vlaskina ◽  
Vladimir P. Sotskov ◽  
...  

Red fluorescent genetically encoded calcium indicators (GECIs) have expanded the available pallet of colors used for the visualization of neuronal calcium activity in vivo. However, their calcium-binding domain is restricted by calmodulin from metazoans. In this study, we developed red GECI, called FRCaMP, using calmodulin (CaM) from Schizosaccharomyces pombe fungus as a calcium binding domain. Compared to the R-GECO1 indicator in vitro, the purified protein FRCaMP had similar spectral characteristics, brightness, and pH stability but a 1.3-fold lower ΔF/F calcium response and 2.6-fold tighter calcium affinity with Kd of 441 nM and 2.4–6.6-fold lower photostability. In the cytosol of cultured HeLa cells, FRCaMP visualized calcium transients with a ΔF/F dynamic range of 5.6, which was similar to that of R-GECO1. FRCaMP robustly visualized the spontaneous activity of neuronal cultures and had a similar ΔF/F dynamic range of 1.7 but 2.1-fold faster decay kinetics vs. NCaMP7. On electrically stimulated cultured neurons, FRCaMP demonstrated 1.8-fold faster decay kinetics and 1.7-fold lower ΔF/F values per one action potential of 0.23 compared to the NCaMP7 indicator. The fungus-originating CaM of the FRCaMP indicator version with a deleted M13-like peptide did not interact with the cytosolic environment of the HeLa cells in contrast to the metazoa-originating CaM of the similarly truncated version of the GCaMP6s indicator with a deleted M13-like peptide. Finally, we generated a split version of the FRCaMP indicator, which allowed the simultaneous detection of calcium transients and the heterodimerization of bJun/bFos interacting proteins in the nuclei of HeLa cells with a ΔF/F dynamic range of 9.4 and a contrast of 2.3–3.5, respectively.


1993 ◽  
Vol 268 (18) ◽  
pp. 13267-13273
Author(s):  
I. Matsuura ◽  
E. Kimura ◽  
K. Tai ◽  
M. Yazawa

2021 ◽  
Author(s):  
Sean Mullany ◽  
Emmanuelle Souzeau ◽  
Sonja Klebe ◽  
Tiger Zhou ◽  
Lachlan S. W. Knight ◽  
...  

2001 ◽  
Vol 17 (1) ◽  
pp. 151-166 ◽  
Author(s):  
Lorenz Vogt ◽  
Sabine P. Schrimpf ◽  
Virginia Meskenaite ◽  
Renato Frischknecht ◽  
Jochen Kinter ◽  
...  

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