Transient expression of wild type and alternative recombinant mutant protein S in COS 1 cells.

The original natural occurring mutants are also shown. Bars represent the mean ± SD of 8 different protein S determinations corresponding to duplicates from 4 different transfections per mutant. A value of 100% was arbitrarily given to the mean value of the wild type expression. Comparison of protein S secretion in the alternative mutants and that in the wild type, as well as that in the original mutants was performed using an unpaired t test. OnlyP-values considered significant (≤ .05) are shown. A comparison of the sequences containing the mutated residues in human and other mammalian protein S and related proteins (human Gas6, human SHBG, and the G4 and G5 repeats in human laminin A) is also shown. Given the high conservation of the protein S sequence around G441 and Y444 in mammals, a consensus sequence from baboon, rabbit, bovine, porcine, murine, and rat PS is shown as mammalian protein S. When there is a difference between human protein S and other mammalian species, this is indicated in the consensus sequence by the different residue followed by the number of species, when more than 1, where this difference is observed. Dots indicate conserved amino acids. For a more complete sequence comparison, see reference 47. The mutated residues are in bold.