TY - JOUR
T1 - Serum stimulation of phospholipase A2 and prostaglandin release in 3T3 cells is associated with platelet-derived growth-promoting activity
AU - Shier, W. T.
PY - 1980
Y1 - 1980
N2 - Sera from mouse, rat, and calf sources stimulate cellular phospholipase A2 acitivity (PLase; phosphatide 2-acylhydrolase, EC 3.1.1.4) and prostaglandin synthesis in 3T3 Swiss mouse fibroblasts, releasing up to 33% of biosynthetically incorporated [3H]arachidonic acid as hydrolysis products in 1 hr. The PLase stimulated by mouse serum exhibits specificity for arachidonic acid residues on phospholipids. It is stimulated 2.5-fold by 1.8 mM Ca2+ in the presence of 5 μM divalent cation ionophore A23187, consistent with a Ca2+-dependent enzyme possessing a cytoplasmic Ca2+ binding site. The percentage maximal PLase- and growth-stimulating activities of the three sera exhibit similar concentration dependencies, with the homologous (mouse) serum exhibiting the highest specific activities. Confluent 3T3 cells deplete PLase-stimulating activity from medium containing calf serum at a rate similar to the depletion of cell growth-stimulating activity. The PLase-stimulating activity in rat and mouse sera is derived from the leukocyte fraction of blood, presumably from platelets. In rat leukocyte lysates the PLase-stimulating activity exhibits properties similar to those reported for platelet-derived cell growth factors from rat and human sources - i.e., stability to exposure to 100°C for 2 min or to pH 2 or pH 11, and cationic properties. Purified preparations of human platelet-derived growth factor also exhibit 3T3 PLase-stimulating activity.
AB - Sera from mouse, rat, and calf sources stimulate cellular phospholipase A2 acitivity (PLase; phosphatide 2-acylhydrolase, EC 3.1.1.4) and prostaglandin synthesis in 3T3 Swiss mouse fibroblasts, releasing up to 33% of biosynthetically incorporated [3H]arachidonic acid as hydrolysis products in 1 hr. The PLase stimulated by mouse serum exhibits specificity for arachidonic acid residues on phospholipids. It is stimulated 2.5-fold by 1.8 mM Ca2+ in the presence of 5 μM divalent cation ionophore A23187, consistent with a Ca2+-dependent enzyme possessing a cytoplasmic Ca2+ binding site. The percentage maximal PLase- and growth-stimulating activities of the three sera exhibit similar concentration dependencies, with the homologous (mouse) serum exhibiting the highest specific activities. Confluent 3T3 cells deplete PLase-stimulating activity from medium containing calf serum at a rate similar to the depletion of cell growth-stimulating activity. The PLase-stimulating activity in rat and mouse sera is derived from the leukocyte fraction of blood, presumably from platelets. In rat leukocyte lysates the PLase-stimulating activity exhibits properties similar to those reported for platelet-derived cell growth factors from rat and human sources - i.e., stability to exposure to 100°C for 2 min or to pH 2 or pH 11, and cationic properties. Purified preparations of human platelet-derived growth factor also exhibit 3T3 PLase-stimulating activity.
UR - http://www.scopus.com/inward/record.url?scp=0018844216&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0018844216&partnerID=8YFLogxK
U2 - 10.1073/pnas.77.1.137
DO - 10.1073/pnas.77.1.137
M3 - Article
C2 - 6928609
AN - SCOPUS:0018844216
SN - 0027-8424
VL - 77
SP - 137
EP - 141
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 1
ER -