Sung TC, Roper RL, Zhang Y, Rudge SA, Temel R, Hammond SM, Morris AJ, Moss B, Engebrecht J, Frohman MA. Mutagenesis of phospholipase D defines a superfamily including a trans-Golgi viral protein required for poxvirus pathogenicity.
EMBO J 1997;
16:4519-30. [PMID:
9303296 PMCID:
PMC1170078 DOI:
10.1093/emboj/16.15.4519]
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Abstract
Phospholipase D (PLD) genes are members of a superfamily that is defined by several highly conserved motifs. PLD in mammals has been proposed to play a role in membrane vesicular trafficking and signal transduction. Using site-directed mutagenesis, 25 point mutants have been made in human PLD1 (hPLD1) and characterized. We find that a motif (HxKxxxxD) and a serine/threonine conserved in all members of the PLD superfamily are critical for PLD biochemical activity, suggesting a possible catalytic mechanism. Functional analysis of catalytically inactive point mutants for yeast PLD demonstrates that the meiotic phenotype ensuing from PLD deficiency in yeast derives from a loss of enzymatic activity. Finally, mutation of an HxKxxxxD motif found in a vaccinia viral protein expressed in the Golgi complex results in loss of efficient vaccinia virus cell-to-cell spreading, implicating the viral protein as a member of the superfamily and suggesting that it encodes a lipid modifying or binding activity. The results suggest that vaccinia virus and hPLD1 may act through analogous mechanisms to effect viral cellular egress and vesicular trafficking, respectively.
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