Effect of fragmin on actin polymerization: evidence for …
Here it is shown that when actin is polymerized at low concentrations of salts, fragmin increases the critical concentration of actin for polymerization. This effect of fragmin on the critical concentration is independent of the molar ratio of fragmin to actin.
Actin Post Translational Modifications and the Cytoskeleton
Actin, a highly expressed and ubiquitous cytoskeletal protein, is a major substrate for at least 17 post-translational modifications (PTMs) 1. PTMs are highly dynamic and often reversible processes where a protein’s functional properties are altered by addition of a chemical group or another protein to its amino acid residues.
Fragmin, a microfilament regulatory protein from Physarum
1996年4月30日 · Fragmin is a 42 kDa regulatory protein involved in actin microfilament organization in Physarum polycephalum. We show that fragmin is a target of casein kinase II (CK II) enzymes isolated from evolutionarily divergent species.
The Actin-binding Properties of the Physarum Actin-Fragmin …
Fragmin possesses two high affinity actin-binding sites and probably also a third, low affinity site. Its nucleating and F-actin severing activities are inhibited by phosphatidylinositol 4,5-bisphosphate (PIP2). Actin-fragmin specifically binds PIP2 which competes with …
Control of actin filament length by phosphorylation of fragmin-actin ...
1990年9月9日 · Fragmin is a Ca2(+)-sensitive F-actin-severing protein purified from a slime mold, Physarum polycephalum (Hasegawa, T., S. Takahashi, H. Hayashi, and S. Hatano. 1980. Biochemistry. 19:2677-2683). It binds to G-actin to form a 1:1 fragmin/actin complex in the presence of micromolar free Ca2+.
Fragmin60 Encodes an Actin-binding Protein with a C2 Domain …
We report the isolation of a cDNA clone encoding a 60-kDa protein termed fragmin60 that cross-reacts with fragmin antibodies. Unlike other gelsolin-related proteins, fragmin60 contains a unique N-terminal domain that shows similarity with C2 domains of aczonin, protein kinase C, and synaptotagmins.
Phosphorylation by actin kinase of the pointed end domain on the actin ...
1992年5月5日 · Fragmin from plasmodium of Physarum polycephalum binds G-actin and severs F-actin in the presence of Ca2+ over 10 (-6) M. The fragmin-actin complex consisting of fragmin and G-actin nucleates actin polymerization and caps the barbed (fast growing) end of F-actin, regardless of the concentrations of Ca2+, and the actin filaments are shortened.
Post-Translational Modifications of Actin - Cytoskeleton
Conversely, in the slime mold Physarum, actin fragmin kinase (AFK), a calcium-dependent enzyme, phosphorylates Thr201-203, leading to elongation of the actin filaments 72-75. This elongation is believed to be a result of reduced interactions between fragmin and actin.
Microfilament dynamics: Regulation of actin polymerization by actin …
1995年1月1日 · Fragmin is a member of the gelsolin family (5), and nucleates, caps and severs actin filaments in a Ca2^ -dependent way. We have investigated the phosphorylation of the actin-fragmin complex as a new way by which the actin cytoskeleton can be regulated.
Physarum actin is phosphorylated as the actin-fragmin complex …
2016年10月6日 · Polymerized actin (vertebrate muscle and non-muscle isoforms) and actin complexes with various actin-binding proteins are poorly phosphorylated. The heterotrimer consisting of two actins and one fragmin, which is formed from cap 42(a+b) and actin in the presence of micromolar concentrations of Ca2+, is also a poor substrate.