Abstract: Described is the production of mammalian cells expressing prohormone convertase which facilitates the processing of prohormone precursors to active hormones. Also described are variant prohormone convertases, and prohormones. The transformed cells of the present invention may be used in the synthesis of properly processed polypeptide hormones, and in cell culture to reduce dependence upon added hormones and required serum polypeptide factors.

Abstract: Provided are animal host cells not naturally capable of forming secretory granules and that produce active, mature insulin by expression of a variant proinsulin containing a non-naturally occurring cleavage site and enzymatic cleavage of the non-naturally occurring cleavage site in the host cells. Further provided are methods of culturing such cells.

Abstract: Methods are provided for the preparation in recombinant host cells of biologically active soluble variants of discretely encoded, heteromultimer polypeptide receptors. Such variants are synthesized by the secretion from recombinant transformants of transmembrane-modified heteromultimer receptors. Preferred receptors are extracellular matrix, cell surface, or plasma protein-binding receptors such as GPIIb-IIIa.

Abstract: Methods are provided for the preparation in recombinant host cells of biologically active soluble variants of discretely encoded, heteromultimer polypeptide receptors. Such variants are synthesized by the secretion from recombinant transformants of transmembrane-modified heteromultimer receptors. Preferred receptors are extracellular matrix, cell surface, or plasma protein-binding receptors such as GPIIb-IIIa.

Abstract: Methods are provided for the preparation in recombinant host cells of biologically active soluble variants of discretely encoded, heteromultimer polypeptide receptors. Such variants are synthesized by the secretion from recombinant transformants of transmembrane-modified heteromultimer receptors. Preferred receptors are extracellular matrix, cell surface, or plasma protein-binding receptors such as GPIIb-IIIa.

Abstract: A method is described for transient production of a desired heterologous protein comprising: transfecting a eukaryotic host cell with a vector producing a trans-activating protein; transfecting the eukaryotic host cell with an expression vector comprising a stabilizing sequence downstream of a promoter and upstream of a DNA encoding the desired heterologous protein and a polyadenylation sequence downstream of which is a transcription terminatein site; culturing the transfected eukaryotic host cell under conditions favorable for production of said desired heterologous protein; and, recovering the desired protein in useful amounts within about one day to about fourteen days of transfection.