Differential Regulation of Saccharomyces cerevisiae Phospholipase D in Sporulation and Sec14-Independent Secretion

Corresponding author: JoAnne Engebrecht, State University of New York, Stony Brook, NY 11794-8651., joanne{at}pharm.sunysb.edu (E-mail)

Communicating editor: A. P. MITCHELL

Saccharomyces cerevisiae Spo14, a phosphatidylcholine-specific, phosphatidylinositol (4,5) bisphosphate-activated phospholipase D (PLD), is essential for meiosis and spore formation. Spo14 is also required for secretion in the absence of the phosphatidylinositol/phosphatidylcholine transfer protein Sec14 (i.e., Sec14-independent secretion). In sporulating cells Spo14 is phosphorylated and relocalized within the cell. In contrast, Spo14 does not relocalize and is not phosphorylated in Sec14-independent secretion. Analysis of a partially phosphatidylinositol (4,5) bisphosphate-activated Spo14 mutant, spo14^R894G, revealed that Spo14 function in Sec14-independent secretion, unlike the situation in meiosis, requires fully stimulated PLD activity. Consistent with the differential regulation of Spo14 function during sporulation and secretion, we isolated a mutant allele, spo14-S251P, the product of which is improperly phosphorylated and fails to relocalize and rescue the sporulation phenotype of homozygous spo14 diploids, but supports Sec14-independent secretion. Furthermore, we show that the N-terminal domain of Spo14 is both phosphorylated and sufficient for prospore membrane localization during sporulation. These data indicate that Spo14 phosphorylation and relocalization are essential for the process of sporulation, but dispensable for Sec14-independent secretion. Finally, we demonstrate that Spo14 phosphorylation and relocalization are initiated by nitrogen and glucose limitation and occur independently of the process of meiosis.

This article has been cited by other articles:

				M. Morishita and J. Engebrecht Sorting Signals within the Saccharomyces cerevisiae Sporulation-Specific Dityrosine Transporter, Dtr1p, C Terminus Promote Golgi-to-Prospore Membrane Transport Eukaryot. Cell, October 1, 2008; 7(10): 1674 - 1684. [Abstract] [Full Text] [PDF]

				J. E. Connolly and J. Engebrecht The Arf-GTPase-Activating Protein Gcs1p Is Essential for Sporulation and Regulates the Phospholipase D Spo14p Eukaryot. Cell, January 1, 2006; 5(1): 112 - 124. [Abstract] [Full Text] [PDF]

				C. G. Riedel, M. Mazza, P. Maier, R. Korner, and M. Knop Differential Requirement for Phospholipase D/Spo14 and Its Novel Interactor Sma1 for Regulation of Exocytotic Vesicle Fusion in Yeast Meiosis J. Biol. Chem., November 11, 2005; 280(45): 37846 - 37852. [Abstract] [Full Text] [PDF]

				S. A. Rudge, V. A. Sciorra, M. Iwamoto, C. Zhou, T. Strahl, A. J. Morris, J. Thorner, and J. Engebrecht Roles of Phosphoinositides and of Spo14p (phospholipase D)-generated Phosphatidic Acid during Yeast Sporulation Mol. Biol. Cell, January 1, 2004; 15(1): 207 - 218. [Abstract] [Full Text] [PDF]

				V. A. Sciorra, S. A. Rudge, J. Wang, S. McLaughlin, J. Engebrecht, and A. J. Morris Dual role for phosphoinositides in regulation of yeast and mammalian phospholipase D enzymes J. Cell Biol., December 23, 2002; 159(6): 1039 - 1049. [Abstract] [Full Text] [PDF]