期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1978
卷号：75
期号：5
页码：2210-2214
DOI：10.1073/pnas.75.5.2210
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The nerve growth factor protein (NGF) favors polymerization of brain actin and induces its organization to form paracrystalline structures that activate myosin ATPase (ATP phosphohydrolase, EC 3.6.1.3 ) to an extent greater than actin alone. Binding studies show that the initial 1:1 stoichiometry of NGF-G-actin complexes decreases to 1:7-10 when polymerization is ended and paracrystalline structures are formed. The ratio becomes even lower when heavy meromyosin is added in the absence of ATP, suggesting that heavy meromyosin displaces NGF bound to actin microfilaments. This conclusion is supported by the finding that when heavy meromyosin is added to NGF-microfilament complexes, under conditions for "decorating" microfilaments, the usual paracrystalline structure of the complexes disappears. The NGF-mediated organization of actin and activation of myosin ATPase is visualized as a self-regulatory and self-propagating mechanism, because progressive displacement of the growth factor induced by heavy meromyosin binding to F actin as ATP consumption proceeds renders an increasingly higher amount of NGF free for new interactions. These findings are discussed in the light of the mechanism of action of NGF in the target cells.
