Abstract |
PKD2, or polycystin 2, the product of the gene mutated in type 2 autosomal dominant polycystic kidney disease, belongs to the transient receptor potential channel superfamily and has been shown to function as a nonselective cation channel in the plasma membrane. However, the mechanism of PKD2 activation remains elusive. We show that PKD2 overexpression increases epidermal growth factor ( EGF)-induced inward currents in LLC-PK(1) kidney epithelial cells, while the knockdown of endogenous PKD2 by RNA interference or the expression of a pathogenic missense variant, PKD2-D511V, blunts the EGF-induced response. Pharmacological experiments indicate that the EGF-induced activation of PKD2 occurs independently of store depletion but requires the activity of phospholipase C (PLC) and phosphoinositide 3-kinase (PI3K). Pipette infusion of purified phosphatidylinositol-4,5-bisphosphate (PIP(2)) suppresses the PKD2-mediated effect on EGF-induced conductance, while pipette infusion of phosphatidylinositol-3,4,5-trisphosphate (PIP(3)) does not have any effect on this conductance. Overexpression of type Ialpha phosphatidylinositol-4-phosphate 5-kinase [PIP(5)Kalpha], which catalyzes the formation of PIP(2), suppresses EGF-induced currents. Biochemical experiments show that PKD2 physically interacts with PLC-gamma2 and EGF receptor (EGFR) in transfected HEK293T cells and colocalizes with EGFR and PIP(2) in the primary cilium of LLC-PK(1) cells. We propose that plasma membrane PKD2 is under negative regulation by PIP(2). EGF may reduce the threshold of PKD2 activation by mechanical and other stimuli by releasing it from PIP(2)-mediated inhibition.
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Authors | Rong Ma, Wei-Ping Li, Dana Rundle, Jin Kong, Hamid I Akbarali, Leonidas Tsiokas |
Journal | Molecular and cellular biology
(Mol Cell Biol)
Vol. 25
Issue 18
Pg. 8285-98
(Sep 2005)
ISSN: 0270-7306 [Print] United States |
PMID | 16135816
(Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)
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Chemical References |
- Ion Channels
- Membrane Proteins
- Phosphatidylinositol 4,5-Diphosphate
- TRPP Cation Channels
- polycystic kidney disease 2 protein
- Epidermal Growth Factor
- Phosphatidylinositol 3-Kinases
- Phosphotransferases (Alcohol Group Acceptor)
- 1-phosphatidylinositol-4-phosphate 5-kinase
- ErbB Receptors
- Type C Phospholipases
- Phospholipase C gamma
- Calcium
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Topics |
- Alleles
- Animals
- Calcium
(metabolism)
- Cell Membrane
(drug effects, metabolism)
- Cilia
(chemistry, drug effects, metabolism)
- Epidermal Growth Factor
(pharmacology)
- ErbB Receptors
(analysis, metabolism)
- Humans
- Ion Channels
(genetics, metabolism)
- Kidney
(cytology)
- LLC-PK1 Cells
- Membrane Proteins
(analysis, genetics, metabolism)
- Mutation, Missense
- Phosphatidylinositol 3-Kinases
(metabolism)
- Phosphatidylinositol 4,5-Diphosphate
(analysis, metabolism, pharmacology)
- Phospholipase C gamma
- Phosphotransferases (Alcohol Group Acceptor)
(metabolism)
- RNA Interference
- Swine
- TRPP Cation Channels
- Type C Phospholipases
(metabolism)
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