Abstract: The present application pertains inter alia to an isolated vertebrate cell suitable for recombinant expression of a polypeptide of interest, wherein the vertebrate cell is altered to impair the function of the endogenous protease matriptase and wherein said cell comprises at least one heterologous polynucleotide encoding a polypeptide of interest and wherein the polypeptide of interest is secreted by the cell. It was found that using respective vertebrate cells for producing a recombinant polypeptide of interest significantly reduces clipping of the polypeptide of interest that is secreted into the cell culture medium. Also provided are improved production and screening methods.

Abstract: The present application pertains inter alia to an isolated vertebrate cell suitable for recombinant expression of a polypeptide of interest, wherein the vertebrate cell is altered to impair the function of the endogenous protease matriptase and wherein the cell comprises at least one heterologous polynucleotide encoding a polypeptide of interest and wherein the polypeptide of interest is secreted by the cell. It was found that using respective vertebrate cells for producing a recombinant polypeptide of interest significantly reduces clipping of the polypeptide of interest that is secreted into the cell culture medium. Also provided are improved production and screening methods.

Abstract: The invention relates to methods for the production of therapeutic proteins in mammalian cells. In one embodiment, the method comprises producing a therapeutic protein such as IGF-1 in a mammalian cell endogenously expressing a cognate receptor of said recombinant therapeutic protein and wherein binding of said therapeutic protein to said cognate receptor results in a low titer of the therapeutic protein, the method comprising with a mammalian cell being deficient in the expression of the cognate receptor of said therapeutic protein and being transformed with an expression vector comprising a nucleic acid molecule encoding the therapeutic protein: a. Cultivating said cell under conditions allowing the expression of the therapeutic protein; and b. Harvesting the therapeutic protein from the mammalian cell cultivated in step a, wherein said mammalian cell produces at least 1.5 fold more therapeutic protein than a cell in which the expression of the cognate receptor has not been so modified.

Abstract: The present application pertains inter alia to an isolated vertebrate cell suitable for recombinant expression of a polypeptide of interest, wherein the vertebrate cell is altered to impair the function of the endogenous protease matriptase and wherein said cell comprises at least one heterologous polynucleotide encoding a polypeptide of interest and wherein the polypeptide of interest is secreted by the cell. It was found that using respective vertebrate cells for producing a recombinant polypeptide of interest significantly reduces clipping of the polypeptide of interest that is secreted into the cell culture medium. Also provided are improved production and screening methods.

Abstract: The invention relates to methods for the production of therapeutic proteins in mammalian cells. In one embodiment, the method comprises producing a therapeutic protein such as IGF-1 in a mammalian cell endogenously expressing a cognate receptor of said recombinant therapeutic protein and wherein binding of said therapeutic protein to said cognate receptor results in a low titer of the therapeutic protein, the method comprising with a mammalian cell being deficient in the expression of the cognate receptor of said therapeutic protein and being transformed with an expression vector comprising a nucleic acid molecule encoding the therapeutic protein: a. Cultivating said cell under conditions allowing the expression of the therapeutic protein; and b. Harvesting the therapeutic protein from the mammalian cell cultivated in step a, wherein said mammalian cell produces at least 1.5 fold more therapeutic protein than a cell in which the expression of the cognate receptor has not been so modified.