title: Nucleation of actin polymerization from profilactin. Opposite effects of different nuclei.
abstract: The lag in polymerization of calf spleen profilactin in response to addition of MgCl2 can be overcome by small amounts of spectrin-actin-band 4.1 complex, covalently crosslinked actin oligomers or sonicated F-actin. All of these factors also nucleate polymerization of pure actin. Another nucleator of actin polymerization, villin, delays filaments formation from profilactin. A simple model of the interaction of profilin with actin can explain these apparently conflicting results in terms of the polarity with which actin filaments elongate from the different nuclei.
mesh_terms: D000199:Actins / Q000378:metabolism*; D000818:Animals; D001798:Blood Proteins / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D003598:Cytoskeletal Proteins; D003599:Cytoskeleton / Q000378:metabolism*; D008274:Magnesium / Q000378:metabolism; D008565:Membrane Proteins; D008840:Microfilament Proteins; D009479:Neuropeptides; D051304:Profilins; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism*; D013049:Spectrin / Q000378:metabolism; D013154:Spleen
chemical_list: D000199:Actins; D001798:Blood Proteins; D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; D008565:Membrane Proteins; D008840:Microfilament Proteins; D009479:Neuropeptides; D051304:Profilins; D011506:Proteins; C028841:erythrocyte membrane band 4.1 protein; C120557:erythrocyte membrane protein band 4.1-like 1; C024782:profilactin; C026615:villin; D013049:Spectrin; D008274:Magnesium