Biochemical and Biophysical Research Communications, Vol.518, No.4, 644-650, 2019
Distinct enzymatic and cellular characteristics of two phospholipases A(1) in Aspergillus oryzae
Phospholipases A(1) (PLA(1)s) catalyze the hydrolysis of sn-1 linkage in the glycerophospholipids, thereby releasing fatty acids and 2-acyl lysophospholipids. PLA(1)s are found in various organisms and tissues where they play diverse cellular functions, but their roles in filamentous fungi remain elusive. In this study we analyzed the enzymatic properties and physiological functions of two secretory PLA(1)s, PLA1-1 and its paralog PLA1-2, in the filamentous fungus Aspergillus oryzae. Although PLA1-1 and PLA1-2 share 49% amino acid sequence identity, they significantly differ in various aspects. While PLA1-1 displayed PLA(1) activity to phosphatidylcholine and phosphatidylethanolamine, and degraded various phospholipids, PLA1-2 exhibited PLA T activity only to phosphatidylglycerol. PLA1-1 was secreted to the culture medium, but PLA1-2 was not secreted and retained in the mycelium. Fluorescence microscopic observation of A. oryzae strains expressing EGFP-fused PLA1-1 and PLA1-2 demonstrated that they display overlapping but distinct cellular localization. A. oryzae mutants deleted for plat-1 or plat-2 grew normally, but the secreted phospholipase activity was significantly reduced in the Delta pla1-1 strain. These data suggest that two sPLA(1) enzymes are not redundant and play distinct cellular functions in A. oryzae. (C) 2019 Elsevier Inc. All rights reserved.
Keywords:Aspergillus oryzae;Fatty acid;Lysophospholipid;Phosphatidylglycerol;Phospholipase A(1);Secretion