Catalytic Properties of ADAM19

Abstract

ADAMs are membrane-anchored glycoproteins with functions in fertilization, heart development, neurogenesis, and protein ectodomain shedding. Here we report an evaluation of the catalytic activity of recombinantly expressed soluble forms of ADAM19, a protein that is essential for cardiovascular morphogenesis. Proteolytic activity of soluble forms of ADAM19 was first demonstrated by their autocatalytic removal of a purification tag (Myc-His) and their ability to cleave myelin basic protein and the insulin B chain. The metalloprotease activity of ADAM19 is sensitive to the hydroxamic acid-type metalloprotease inhibitor BB94 (batimastat) but not to tissue inhibitors of metalloproteases (TIMPs) 1-3. Moreover, ADAM19 cleaves peptides corresponding to the known cleavage sites of tumor necrosis factor-alpha (TNF-alpha), TNF-related activation-induced cytokine (TRANCE, also referred to as osteoprotegerin ligand), and kit ligand-1 (KL-1) in vitro. Although ADAM19 is not required for shedding of TNFalpha and TRANCE in mouse embryonic fibroblasts, its overexpression in COS-7 cells results in strongly increased TRANCE shedding. This suggests a potential role for ADAM19 in shedding TRANCE in cells where both molecules are highly expressed, such as in osteoblasts. Interestingly, our results also indicate that ADAM19 can function as a negative regulator of KL-1 shedding in both COS-7 cells and mouse embryonic fibroblasts, instead of acting directly on KL-1. The identification of potential in vitro substrates offers the basis for further functional studies of ADAM19 in cells and in mice.

Expression of ADAMs (“a disintegrin and metalloprotease”) in the human lung

“…ADAM19 can, besides TNF-alpha, release tumor necrosis factor-related activation-induced cytokine (TRANCE) [20]. TRANCE is part of the tumor necrosis factor superfamily and has an immunity-modulating role as well.…”

“…This may well be initiated by shedding of c-kit ligand. Not only ADAM33 [32] but also ADAM8 [33], ADAM9 [34], ADAM17 [35,36], and ADAM19 [20] are capable of shedding of c-kit ligand, also known as stem cell factor (SCF). SCF plays, apart from its main role as hemopoietic growth factor, a role in recruitment and in maturation of mast cell progenitors [37], sustaining the survival and maintaining phenotypic properties of mast cells in mucosal tissues [38,39].…”

α-Lipoic acid suppresses osteoclastogenesis despite increasing the receptor activator of nuclear factor κB ligand/osteoprotegerin ratio in human bone marrow stromal cells

“…TNF-is thought to be released from the plasma membrane by the metalloprotease-disintegrin TNF-convertase (TACE) (Black et al 1997). Similarly, RANKL shedding has been shown to be catalyzed by TACE, by the membranous metalloprotease MT1-MMP or by A-disintegrin and metalloprotease 19 (Lum et al 1999, Chesneau et al 2003. Since shedding of many cell surface proteins can be inhibited with metalloprotease inhibitors, we tested the ability of these inhibitors to affect soluble RANKL production.…”

O-Linked Glycosylation at Threonine 27 Protects the Copper Transporter hCTR1 from Proteolytic Cleavage in Mammalian Cells

“…4). reported (37)(38)(39)(40) as well as examples of internalization and subsequent cleavage (41). We are currently in the process of investigating these issues.…”