Molecular and enzymatic properties of furin, a Kex2-like endoprotease involved in precursor cleavage at Arg-X-Lys/Arg-Arg sites.
We have recently shown that furin, a mammalian homologue of the yeast precursor-processing endoprotease Kex2, is involved in precursor cleavage at sites marked by the Arg-X-Lys/Arg-Arg motif within the constitutive secretory pathway. In this study, we analyzed molecular and enzymatic properties of furin expressed in Chinese hamster ovary cells using gene transfer techniques. COOH-terminal truncation analyses indicate that the polypeptide region significantly conserved among the Kex2 family members is required for the endoprotease activity of furin, while the COOH-terminal unconserved region containing the Cys-rich domain and the transmembrane domain is dispensable. A mutant of furin truncated up to the transmembrane domain from the COOH-terminus was secreted into the culture medium as an active form. The sequence requirements for precursor cleavage of this truncated furin determined in vitro were similar to those of wild-type furin determined by expression studies in cultured cells. It had a strong resemblance to the Kex2 protease in the inhibitor profile and pH dependency. These observations support the notion that furin is the endogenous endoprotease involved in precursor cleavage at Arg-X-Lys/Arg-Arg sites.
Hatsuzawa
K
K
Institute of Applied Biochemistry, University of Tsukuba, Ibaraki.
Murakami
K
K
Nakayama
K
K
D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D004591:Electrophoresis, Polyacrylamide Gel; D045683:Furin; D008565:Membrane Proteins / Q000032:analysis / Q000502:physiology*; D013381:Subtilisins / Q000032:analysis / Q000037:antagonists & inhibitors / Q000502:physiology*; D014162:Transfection
D008565:Membrane Proteins; D013381:Subtilisins; D045683:Furin