Linked Life Data

1333365

Source:http://linkedlifedata.com/resource/pubmed/id/1333365

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1993-1-6
pubmed:abstractText
The fast and transient polymerization of actin in nonmuscle cells after stimulation with chemoattractants requires strong nucleation activities but also components that inhibit this process in resting cells. In this paper, we describe the purification and characterization of a new actin-binding protein from Dictyostelium discoideum that exhibited strong F-actin capping activity but did not nucleate actin assembly independently of the Ca2+ concentration. These properties led at physiological salt conditions to an inhibition of actin polymerization at a molar ratio of capping protein to actin below 1:1,000. The protein is a monomer, with a molecular mass of approximately 100 kDa, and is present in growing and in developing amoebae. Based on its F-actin capping function and its apparent molecular weight, we designated this monomeric protein cap100. As shown by dilution-induced depolymerization and by elongation assays, cap100 capped the barbed ends of actin filaments and did not sever F-actin. In agreement with its capping activity, cap100 increased the critical concentration for actin polymerization. In excitation or emission scans of pyrene-labeled G-actin, the fluorescence was increased in the presence of cap100. This suggests a G-actin binding activity for cap100. The capping activity could be completely inhibited by phosphatidylinositol 4,5-bisphosphate (PIP2), and bound cap100 could be removed by PIP2. The inhibition by phosphatidylinositol and the Ca(2+)-independent down-regulation of spontaneous actin polymerization indicate that cap100 plays a role in balancing the G- and F-actin pools of a resting cell. In the cytoplasm, the equilibrium would be shifted towards G-actin, but, below the membrane where F-actin is required, this activity would be inhibited by PIP2.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0886-1544
pubmed:author
pubmed:issnType
Print
pubmed:volume
23
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
133-44
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Cap100, a novel phosphatidylinositol 4,5-bisphosphate-regulated protein that caps actin filaments but does not nucleate actin assembly.
pubmed:affiliation
Max-Planck-Institute for Biochemistry, Martinsried, Federal Republic of Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't