Viscometric analysis of the gelation of Acanthamoeba extracts and purification of two gelation factors.
Year: 1980
Type: article
Abstract: We have studied the kinetics of the gelation process that occurs upon warming cold extracts of Acanthamoeba using a low-shear falling ball assay. We find that the reaction has at least two steps, requires 0.5 mM ATP and 1.5 mM MgCl2, and is inhibited by micromolar Ca++. The optimum pH is 7.0 and temperature, 25 degrees-30 degrees C. The rate of the reaction is increased by cold preincubation with both MgCl2 and ATP. Nonhydrolyzable analogues of ATP will not substitute for ATP either in this "potentiation reaction" or in the gelation process. Either of two purified or any one of four partially purified Acanthamoeba proteins will cross-link purified actin to form a gel, but none can account for the dependence of the reaction in the crude extract on Mg-ATP or its regulation by Ca++. This suggests that the extract contains, in addition to actin-cross-linking proteins, factors dependent on Mg-ATP and Ca++ that regulate the gelation process.
Source: The Journal of Cell Biology
DOI: 10.1083/jcb.85.2.414
Authors: S D MacLean-Fletcher, T D Pollard
Institutions: Johns Hopkins University, Johns Hopkins Medicine
Language: English
Subfield: Cell Biology
Domain: Life Sciences
Open Access status: bronze
OpenAlex ID: W1988312243