PKD2 functions as an epidermal growth factor-activated plasma membrane channel.

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.

• 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.)

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

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)