High impact information on C1s

• This similarity extends to the serine protease component, which shares a similar modular construction and about 40% sequence identity with the C1r and C1s subcomponents of C1 [1].
• Hence, although the RaRF protease and C1s have similar structures and play similar roles in C activation, they also display clear differences in substrate range and in the details of their substrate recognition mechanisms [1].
• This polypeptide is not the C1s in mouse C1 because the sizes of this polypeptide and of the fragments produced by its reduction were different from those of DFP-binding proteinases in mouse C1 [2].
• An intron splits the protein coding sequence precisely at the site of proteolytic activation of C4 by complement protease C1s; however, except for this one case, the intron positions show no striking relationship to the structural features of the C4 protein [3].
• It was shown that the C3a receptor C1r and C1s genes form an unexpected complement gene cluster towards the telomeric end of chromosome 6 [4].

Biological context of C1s

• C1r and C1s are highly specific serine proteases that initiate the classical pathway of complement activation [5].

Other interactions of C1s

• A neoepitope-based enzyme immunoassay for quantification of C1-inhibitor in complex with C1r and C1s [6].

References