Related Experiment Video
Updated: Aug 9, 2026
12:47
Spectral Karyotyping to Study Chromosome Abnormalities in Humans and Mice with Polycystic Kidney Disease
Published on: February 3, 2012
The gating of polycystin signaling complex
1Laboratoire de NeuroPhysiologie Cellulaire, CNRS-UMR 6150, Faculté de Médecine, IFR Jean Roche, Bd. Pierre Dramard, 13916 Marseille 20, France. delmas.p@jean-roche.univ-mrs.fr
Biological Research
|February 16, 2005
Summary
Mutations in polycystin proteins cause autosomal dominant polycystic kidney disease (ADPKD). This study reveals how polycystin-1 regulates polycystin-2 channel gating, explaining ADPKD mechanisms and polycystin functions in various cells.
Area of Science:
- Molecular Biology
- Cell Biology
- Nephrology
Background:
- Mutations in polycystin-2 (PC2) or polycystin-1 (PC1) cause autosomal dominant polycystic kidney disease (ADPKD).
- PC1 and PC2 are believed to function in a common signaling pathway.
- The precise function of PC1 and its interaction with PC2 remain largely unknown.
Purpose of the Study:
- To elucidate the functional relationship between PC1 and PC2.
- To understand the mechanism by which PC1 regulates PC2.
- To provide a mechanistic explanation for ADPKD pathogenesis.
Main Methods:
- Investigated the co-assembly of full-length PC1 and PC2 proteins.
- Analyzed the structural rearrangements within the polycystin complex.
- Examined the ion channel activity and G-protein coupling of the polycystin complex.
Main Results:
- PC1 and PC2 co-assemble to form an ion channel signaling complex.
- PC1 regulates PC2 channel gating via structural rearrangement of the complex.
- Polycystin complexes function as either receptor-cation channels or G-protein-coupled receptors.
Conclusions:
- PC1 acts as a membrane receptor regulating G-proteins, and PC2 functions as a bimodal ion channel.
- This mechanism explains the diverse roles of polycystins in various cell types.
- Impaired polycystin signaling due to genetic alterations likely underlies ADPKD pathogenesis.
Related Concept Videos
01:30Assembly of Signaling Complexes
Multiprotein signaling complexes are formed in a dynamic process involving protein-protein interactions at the cytoplasmic domain of transmembrane receptors or enzymatic and non-enzymatic proteins associated with the receptor. These complexes ensure the activation and propagation of intracellular signals that regulate cell functions.
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...
01:19Interactions Between Signaling Pathways
Signaling cascades usually lack linearity. Multiple pathways interact and regulate one another, allowing cells to integrate and respond to diverse environmental stimuli.
Convergence and divergence, and cross-talk between signaling pathways
Two distinct signaling pathways can converge on a single functional unit, which may either be a single protein or a complex of proteins. The response is either functionally distinct or synergistic between the two pathways but different from the response...
Convergence and divergence, and cross-talk between signaling pathways
Two distinct signaling pathways can converge on a single functional unit, which may either be a single protein or a complex of proteins. The response is either functionally distinct or synergistic between the two pathways but different from the response...
01:22Amplifying Signals via Enzymatic Cascade
When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze the...
01:12GPCR Desensitization
G protein-coupled receptor (GPCR) signaling plays a crucial role in cell functioning. GPCR desensitization is an equally essential process. It allows cells to respond to changing environments and regain sensitivity to new stimuli while preventing unnecessary stimulation when no longer needed. Prolonged exposure to stimuli leads to GPCR desensitization. It involves blocking the receptors from binding and activating additional G proteins. This inhibits activation of downstream effectors, thereby...
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...
01:16Calmodulin-dependent Signaling
Calmodulin (CaM) is a calcium-binding protein in eukaryotes that controls various calcium-regulated cellular processes. It has four calcium-binding sites that bind calcium to form the calcium-calmodulin ( Ca2+-CaM) complex. GPCR stimulation increases the calcium levels in the cells that bind to CaM and induces a conformational change.
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...