Prorenin processing by cathepsin B in vitro and in transfected cells.
نویسندگان
چکیده
Renin, which catalyzes the initial proteolytic cleavage reaction in the production of angiotensins, is first synthesized as a zymogen, prorenin, and requires the proteolytic removal of an amino-terminal prosegment for activation in vivo. The lysosomal hydrolase cathepsin B has been proposed as a prorenin processing enzyme based on reports of its co-localization with renin in the secretory granules of certain tissues and its ability to activate prorenin in vitro. In the current study, scanning mutagenesis was used to identify the amino acids which determine the site selectivity of prorenin cleavage by human cathepsin B in vitro. Co-expression assays in AtT-20 cells were also used to test for the ability of cathepsin B to cleave human prorenin within cells. Our results suggest that a basic lysine residue at the -2 position from the cleavage site is required for cathepsin B cleavage of prorenin in vitro and that the structure of prorenin itself may account for the selection of the proper cleavage site. In addition, although cathepsin B appears to be correctly sorted to lysosomes, the enzyme exhibits prorenin processing activity in transfected AtT-20 cells, raising the question of the cellular localization in which the processing event occurs.
منابع مشابه
Hydrolysis by cathepsin B of fluorescent peptides derived from human prorenin.
Cathepsin B is a lysosomal thiolprotease that, because of its colocalization with renin and its ability to activate prorenin, has been proposed as a prorenin processing enzyme. To characterize the biochemical aspect of this potential cathepsin B activity in more detail, we synthesized and assayed with human cathepsin B the internally quenched fluorescent peptide Abz-FSQPMKRLTLGNTTQ-EDDnp (Abz, ...
متن کاملCathepsin B is not the processing enzyme for mouse prorenin Reudelhuber: Mouse prorenin processing enzyme
Renin, an aspartyl protease that catalyzes the rate-limiting step in the renin angiotensin system (RAS), is proteolytically activated by a second protease (referred to as the prorenin processing enzyme or PPE) before its secretion from the juxtaglomerular (JG) cells of the kidney. Although several enzymes are capable of activating renin in vitro, the leading candidate for the PPE in the kidney ...
متن کاملCathepsin B is not the processing enzyme for mouse prorenin.
Renin, an aspartyl protease that catalyzes the rate-limiting step in the renin-angiotensin system (RAS), is proteolytically activated by a second protease [referred to as the prorenin processing enzyme (PPE)] before its secretion from the juxtaglomerular cells of the kidney. Although several enzymes are capable of activating renin in vitro, the leading candidate for the PPE in the kidney is cat...
متن کاملProteases Detection of invitro Culture of Midgut Cells from Hyalomma anatolicum anatolicum (Acari: Ixodidae)
Proteases play a key role in protein digestion in ticks and other haematophagous insects. Our understanding of blood meal digestion in digestive system of ticks can be very useful for better understanding of basic rules for control of ticks. Cells of the midgut endocytose blood components. Blood proteins uptake by midgut cells, suggesting the presence of proteases in the midgut cells. In this...
متن کاملTwists and turns in the search for the elusive renin processing enzyme: focus on "Cathepsin B is not the processing enzyme for mouse prorenin".
HAVING WORKED FOR MANY YEARS on relatively basic questions germane to the venerable renin-angiotensin system, we were musing with some fascination recently on the continuing evolution of our understanding of the system. In particular, we were taking note of the considerable amount of dogma, with varying levels of verification associated with the system, as well as the almost continuous infusion...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- FEBS letters
دوره 443 1 شماره
صفحات -
تاریخ انتشار 1999