Related Experiment Video
Updated: Aug 7, 2026
08:49
Fluorescence-Based Measurements of Phosphatidylserine/Phosphatidylinositol 4-Phosphate Exchange Between Membranes
Published on: March 14, 2021
Prostasin regulates epithelial monolayer function: cell-specific Gpld1-mediated secretion and functional role for GPI
George M Verghese1, Michael F Gutknecht, George H Caughey
1Department of Medicine, University of Virginia, Charlottesville, Virginia 22908-0546, USA. gmv4n@virginia.edu
American Journal of Physiology. Cell Physiology
|July 11, 2006
Summary
Prostasin, a protease regulating ion channels, is secreted via GPI anchor cleavage in kidney cells. This process controls epithelial barrier function and ion transport, with tissue-specific variations.
Area of Science:
- Biochemistry
- Cell Biology
- Physiology
Background:
- Prostasin is a serine peptidase found in prostate, kidney, and lung epithelia.
- It activates the epithelial sodium channel (ENaC) and inhibits cancer cell invasion.
- Its precise mechanisms of membrane anchoring and secretion were not fully understood.
Purpose of the Study:
- To elucidate the mechanisms of prostasin membrane anchoring and secretion in kidney and lung epithelial cells.
- To determine the role of prostasin in regulating epithelial monolayer function.
- To investigate the specific pathways controlling prostasin secretion and function.
Main Methods:
- Site-directed mutagenesis
- Detergent phase separation
- RNA interference
- Stable transfection of M-1 cells
- Analysis of transepithelial resistance, current, and permeability
Main Results:
- Endogenous mouse prostasin is GPI-anchored and secreted from the apical surface of kidney cells.
- Prostasin secretion is dependent on GPI anchor cleavage by GPI-specific phospholipase D1 (Gpld1).
- Prostasin regulates transepithelial resistance, current, and permeability through GPI anchor and protease activity.
Conclusions:
- Prostasin plays a critical role in regulating epithelial monolayer resistance and permeability in kidney cells.
- Its functions in ion transport are dependent on both its GPI anchor and peptidase activity.
- Tissue-specific pathways for prostasin secretion may dictate its diverse functions.
Related Concept Videos
01:29GPI Anchoring of Proteins in the ER Membrane
GPI-anchoring is a post-translational, reversible protein modification that is ubiquitous in eukaryotes. Such proteins are primarily present on the exoplasmic leaflet of the plasma membrane.
GPI-anchor structure
A sequence of 11 enzymatic reactions results in the synthesis of the complete GPI anchor consisting of a hydrophobic and a hydrophilic portion. The hydrophobic portion comprises phosphatidylinositol, while the hydrophilic part comprises polar groups like phosphoethanolamine,...
GPI-anchor structure
A sequence of 11 enzymatic reactions results in the synthesis of the complete GPI anchor consisting of a hydrophobic and a hydrophilic portion. The hydrophobic portion comprises phosphatidylinositol, while the hydrophilic part comprises polar groups like phosphoethanolamine,...
01:42Phosphoinositides and PIPs
Phosphoinositides are a group of phospholipids containing a glycerol backbone with two fatty acid chains and a phosphate attached to a myoinositol sugar ring. The inositol head group extends into the cytoplasm, where it is modified by adding phosphate groups to form phosphatidylinositol phosphates or PIPs.
Different phosphoinositides are synthesized and recruited on the cytosolic face of the plasma membrane. The localization of specific phosphoinositides concentrated in separate membrane...
Different phosphoinositides are synthesized and recruited on the cytosolic face of the plasma membrane. The localization of specific phosphoinositides concentrated in separate membrane...
01:32Lipids as Anchors
In the plasma membrane, the lipids forming the bilayer can also act as an anchor to tether proteins to the membrane. The three main types of lipid anchors found in eukaryotes are – prenyl groups, fatty acyl groups, and glycosylphosphatidylinositol or GPI groups. Prenyl and fatty acyl groups act as anchors on the cytosolic surface of the membrane, whereas GPI anchors proteins on the extracellular side.
The carboxy-terminal of most of the prenylated proteins, such as Ras proteins, contains the...
The carboxy-terminal of most of the prenylated proteins, such as Ras proteins, contains the...
01:33Coat Assembly and GTPases
Vesicles incorporate different coat protein subunits in different cell locations, which changes the properties of the coat, such as the shape and geometry of the transport vesicles. Thus, vesicle coat proteins also play a significant role in cargo selection.
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...
02:14GTPases and their Regulation
Guanine nucleotide-binding proteins (G-proteins), also known as GTPases, are a superfamily of proteins that regulate many cellular processes, such as cell signaling, vesicular transport, and the regulation of cell shape and motility. Mutation or dysfunction of these proteins can lead to disease. There are around 40,000 known G-proteins that can broadly be classified into two groups ‒ small G-proteins consisting of a single domain and large multi-domain G-proteins.
Large G-proteins, also known...
Large G-proteins, also known...
01:11IP3/DAG Signaling Pathway
Membrane lipids such as phosphatidylinositol (PI) are precursors for several membrane-bound and soluble second messengers. Specific kinases phosphorylate PI and produce phosphorylated inositol phospholipids. One such inositol phospholipids are the phosphatidylinositol-4,5 bisphosphate [PI(4,5)P2], present in the inner half of the lipid bilayer. Upon ligand binding, GPCR stimulates Gq proteins to turn on phospholipase Cꞵ. Activated phospholipase Cꞵ cleaves PI(4,5)P2 and produces two-second...