Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P01034 (cystatin C)
 3,397 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cystatin M/E is a high affinity inhibitor of the asparaginyl endopeptidase legumain, and we have previously reported that both proteins are likely to be involved in the regulation of stratum corneum formation in skin. Although cystatin M/E contains a predicted binding site for papain-like cysteine proteases, no high affinity binding for any member of this family has been demonstrated so far. We report that human cathepsin V (CTSV) and human cathepsin L (CTSL) are strongly inhibited by human cystatin M/E. Kinetic studies show that Ki values of cystatin M/E for the interaction with CTSV and CTSL are 0.47 and 1.78 nM, respectively. On the basis of the analogous sites in cystatin C, we used site-directed mutagenesis to identify the binding sites of these proteases in cystatin M/E. We found that the W135A mutant was rendered inactive against CTSV and CTSL but retained legumain-inhibiting activity. Conversely, the N64A mutant lost legumain-inhibiting activity but remained active against the papain-like cysteine proteases. We conclude that legumain and papain-like cysteine proteases are inhibited by two distinct non-overlapping sites. Using immunohistochemistry on normal human skin, we found that cystatin M/E co-localizes with CTSV and CTSL. In addition, we show that CTSL is the elusive enzyme that processes and activates epidermal transglutaminase 3. The identification of CTSV and CTSL as novel targets for cystatin M/E, their (co)-expression in the stratum granulosum of human skin, and the activity of CTSL toward transglutaminase 3 strongly imply an important role for these enzymes in the differentiation process of human epidermis.
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PMID:Cystatin M/E is a high affinity inhibitor of cathepsin V and cathepsin L by a reactive site that is distinct from the legumain-binding site. A novel clue for the role of cystatin M/E in epidermal cornification. 1656 75

The development of hypertension involves extensive arterial wall remodeling, in which cysteine proteases play an essential role. Cathepsin L/V has been reported to be a cysteine protease that is closely intertwined with the tissue inflammatory response and extracellular matrix accumulation, allowing it to regulate arterial remodeling. The aim of this study was to determine the role of cathepsin L/V and its regulatory pathway in vascular remodeling in hypertension. We showed that cathepsin L/V and its endogenous inhibitor cystatin C, as well as mitogen-activated protein kinase (MEK) phosphorylation, were upregulated in the mesenteric arteries and serum of hypertensive patients. Using a model of angiotensin II-induced hypertension, we observed an increase in aortic artery media thickness, cathepsin L activity, blood pressure and MEK phosphorylation. Treatment with the cathepsin L inhibitor Z-FF-FMK or the genetic deletion of cathepsin L significantly attenuated angiotensin II-induced hypertension, arterial remodeling, cathepsin L activation and MEK phosphorylation. In addition, siRNA-cathepsin V significantly blocked angiotensin II-induced MEK and extracellular signal-regulated kinase (ERK) phosphorylation but not cell proliferation in human aortic smooth muscle cells (HASMCs). Further treatment with the ERK phosphorylation inhibitor U0126 also blocked angiotensin II-induced HASMCs proliferation. The results indicate that the inhibition of cathepsin L prevents arterial remodeling and hypertension, in part by inhibiting the MEK-ERK signaling-mediated regulation of smooth muscle cell proliferation in the vessel wall.
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PMID:Angiotensin II-Induced vascular remodeling and hypertension involves cathepsin L/V- MEK/ERK mediated mechanism. 3166 7