Identification of a Glycerophosphocholine Phosphodiesterase, GDE5, in chicken

Glycerophosphodiester phosphodiesterase (GDPD/GDE) catalyzes the hydrolysis of glycerophosphodiesters to glycerol 3-phosphate and alcohol. It was discovered that the glycerophosphodiesterase family plays a role in lipid metabolism and signal pathway in recent years, but little has been known about the characteristics of chicken GDEs. Here, chicken GDE5 (cGDE5) was identified and characterized for the first time. The full length coding cDNA sequence of cGDE5 was cloned, which encoded a polypeptide with 678 amino acids containing a carbohydrate-binding module 20 (CBM20) and a GDPD domain. Tissue expression profiles showed that cGDE5 mRNA was high in various tissues. such as heart, brain, skeletal muscle and testis. Moreover, cGDE5 was demonstrated to exhibit glycerophosphocholine phosphodiesterase activity. These results together suggested that cGDE5, as a unique member of GDE family, may play multiple roles as a cytoplasmic glycerophosphocholine phosphodiesterase.

Glycerophosphocholine-dependent Growth Requires Gde1p (YPL110c) and Git1p in Saccharomyces cerevisiae

Glycerophosphocholine is formed via the deacylation of the phospholipid phosphatidylcholine. The protein encoded by Saccharomyces cerevisiae open reading frame YPL110c effects glycerophosphocholine metabolism in vivo, most likely by acting as a glycerophosphocholine phosphodiesterase. Deletion of YPL110c causes an accumulation of glycerophosphocholine in cells prelabeled with [14C]choline. Correspondingly, overexpression of YPL110c results in reduced intracellular glycerophosphocholine in cells prelabeled with [14C]choline. Glycerophospho[3H]choline supplied in the growth medium accumulates to a much greater extent in the intracellular fraction of a YPL110Δ strain than in a wild type strain. Furthermore, glycerophospho[3H]choline accumulation requires the transporter encoded by GIT1, a known glycerophosphoinositol transporter. Growth on glycerophosphocholine as the sole phosphate source requires YPL110c and the Git1p permease. In contrast to glycerophosphocholine, glycerophosphoinositol metabolism is unaffected by deletion of YPL110c. The open reading frame YPL110c has been termed GDE1.