Dependence on the Lazaro phosphatidic acid phosphatase for the maximum light response.
The Drosophila phototransduction cascade serves as a paradigm for characterizing the regulation of sensory signaling and TRP channels in vivo . Activation of these channels requires phospholipase C (PLC) and may depend on subsequent production of diacylglycerol (DAG) and downstream metabolites . DAG could potentially be produced through a second pathway involving the combined activities of a phospholipase D (PLD) and a phosphatidic acid (PA) phosphatase (PAP). However, a role for a PAP in the regulation of TRP channels has not been described. Here, we report the identification of a PAP, referred to as Lazaro (Laza). Mutations in laza caused a reduction in the light response and faster termination kinetics. Loss of laza suppressed the severity of the phenotype caused by mutation of the DAG kinase, RDGA , indicating that Laza functions in opposition to RDGA. We also showed that the retinal degeneration resulting from overexpression of the PLD was suppressed by elimination of Laza. These data demonstrate a requirement for a PLD/PAP-dependent pathway for achieving the maximal light response. The genetic interactions with both rdgA and Pld indicate that Laza functions in the convergence of both PLC- and PLD-coupled signaling in vivo.
Kwon
Young
Y
Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
Montell
Craig
C
D000818:Animals; D019852:Diacylglycerol Kinase / Q000378:metabolism; D004330:Drosophila / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D007700:Kinetics; D008027:Light; D046529:Microscopy, Electron, Transmission; D009154:Mutation; D010716:Phosphatidylinositols / Q000378:metabolism; D010739:Phospholipase D / Q000235:genetics / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D012160:Retina / Q000378:metabolism / Q000648:ultrastructure; D014785:Vision, Ocular / Q000502:physiology*
D029721:Drosophila Proteins; D010716:Phosphatidylinositols; D019852:Diacylglycerol Kinase; C511350:RdgA protein, Drosophila; C509828:laza protein, Drosophila; D010744:Phosphoric Monoester Hydrolases; D010739:Phospholipase D