Christopher J. Passero

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Proteolytic processing of epithelial sodium channel (ENaC) subunits occurs as channels mature within the biosynthetic pathway. The proteolytic processing events of the alpha and gamma subunits are associated with channel activation. Furin cleaves the alpha subunit ectodomain at two sites, releasing an inhibitory tract and activating the channel. However,(More)
This is a case of IgG4-related systemic disease (ISD) and its rare renal manifestation as membranous nephropathy (MGN). The patient presented with peripheral edema, hematuria and proteinuria. 24-h urine revealed proteinuria of up to 15 g/d. Renal biopsy revealed MGN and many IgG4-positive plasma cells. Serum IgG4 levels were elevated at 750 mg/dl (9 - 89(More)
Acid-sensing ion channels are proton-gated Na(+) channels expressed predominantly in neurons. How channel structure translates an environmental stimulus into changes in pore permeability remains largely undefined. The pore of ASIC1 is defined by residues in the second transmembrane domain (TM2), although a segment of the outer vestibule is formed by(More)
Proteases activate the epithelial sodium channel (ENaC) by cleaving the large extracellular domains of the α- and γ-subunits and releasing peptides with inhibitory properties. Furin and prostasin activate mouse ENaC by cleaving the γ-subunit at sites flanking a 43 residue inhibitory tract (γE144-K186). To determine whether there is a minimal inhibitory(More)
EXPANSION OF EXTRACELLULAR VOLUME manifests as peripheral and pulmonary edema in chronic heart failure (CHF) patients and can lead to hospitalizations and death (1, 10). Stimulation of the autonomic nervous system, elevated levels of arginine vasopressin (AVP), and activation of the renin-angiotensinaldosterone systems are thought to contribute to the(More)
The epithelial sodium channel (ENaC) is activated by a unique mechanism, whereby inhibitory tracts are released by proteolytic cleavage within the extracellular loops of two of its three homologous subunits. While cleavage by furin within the biosynthetic pathway releases one inhibitory tract from the α-subunit and moderately activates the channel, full(More)
PURPOSE OF REVIEW Hypertension and edema are clinical manifestations of the extracellular volume expansion generated by abnormal renal sodium handling. Perturbations in epithelial sodium channel (ENaC) activity disrupt volume homeostasis. ENaC activity can be enhanced by proteases that cleave its long extracellular domains. Recent evidence suggests that(More)
Epithelial Na(+) channels (ENaCs) play an essential role in the regulation of body fluid homeostasis. Certain transition metals activate or inhibit the activity of ENaCs. In this study, we examined the effect of extracellular Cu(2+) on human ENaC expressed in Xenopus oocytes and investigated the structural basis for its effects. External Cu(2+) inhibited(More)
Marcelo D. Carattino, Christopher J. Passero, Carlos A. Steren, Ahmad B. Maarouf, Joseph M. Pilewski, Mike M. Myerburg, Rebecca P. Hughey, and Thomas R. Kleyman Renal-Electrolyte Division and Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, and Department of Cell Biology and Physiology, University of Pittsburgh,(More)
Passero CJ, Mueller GM, Myerburg MM, Carattino MD, Hughey RP, Kleyman TR. TMPRSS4-dependent activation of the epithelial sodium channel requires cleavage of the -subunit distal to the furin cleavage site. Am J Physiol Renal Physiol 302: F1–F8, 2012. First published October 12, 2011; doi:10.1152/ajprenal.00330.2011.—The epithelial sodium channel (ENaC) is(More)
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