Function of intracellular phospholipase A2 in vectorial transport of apoproteins from ER to Golgi.
1. The cytosolic fraction required in in vitro reconstituted intracellular transport of mucus glycoprotein apopeptide (apomucin) was isolated and its potential as transport supporting factor assessed by the quantitation of the gastric apomucin transferred to Golgi. 2. The experiments with the fraction promoting transport and delivery of apomucin to Golgi revealed that the active protein has the property of phospholipase A2 (PLA2) which assists ER vesicles fusion with Golgi. 3. The ability of the 76 kDa PLA2 to hydrolyze phospholipids and to support transport and fusion of ER vesicles with Golgi was abolished by phosphorylation and regained following dephosphorylation. 4. The data provide evidence that 76 kDa intracellular PLA2 is responsible for the fusion of ER-transport vesicles with Golgi. The process of fusion is accomplished by generation of lysophospholipids in fusing membranes.
Slomiany
A
A
Research Center, University of Medicine and Dentistry of New Jersey, Newark 07103-2400.
Grzelinska
E
E
Kasinathan
C
C
Yamaki
K
K
Palecz
D
D
Slomiany
B L
BL
D000818:Animals; D001059:Apoproteins / Q000378:metabolism*; D001692:Biological Transport; D003600:Cytosol / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005033:Ethylmaleimide / Q000494:pharmacology; D005752:Gastric Mucins; D006056:Golgi Apparatus / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism; D010741:Phospholipases A / Q000378:metabolism*; D054467:Phospholipases A2; D010766:Phosphorylation; D051381:Rats; D013379:Substrate Specificity
D001059:Apoproteins; D005752:Gastric Mucins; D010455:Peptides; C053366:apomucin; D010741:Phospholipases A; D054467:Phospholipases A2; D005033:Ethylmaleimide