Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1992-12-2
pubmed:abstractText
Actin filaments (F-actin) are important determinants of cellular shape and motility. These functions depend on the collective organization of numerous filaments with respect to both position and orientation in the cytoplasm. Much of the orientational organization arises spontaneously through liquid crystal formation in concentrated F-actin solutions. In studying this phenomenon, we found that solutions of purified F-actin undergo a continuous phase transition, from the isotropic state to a liquid crystalline state, when either the mean filament length or the actin concentration is increased above its respective threshold value. The phase diagram representing the threshold filament lengths and concentrations at which the phase transition occurs is consistent with that predicted by Flory's theory on solutions of noninteracting, rigid cylinders (Flory, 1956b). However, in contrast to other predictions based on this model, we found no evidence for the coexistence of isotropic and anisotropic phases. Furthermore, the phase transition proved to be temperature dependent, which suggests the existence of orientation-dependent interfilament interactions or of a temperature-dependent filament flexibility. We developed a simple method for growing undistorted fluorescent acrylodan-labeled F-actin liquid crystals; and we derived a simple theoretical treatment by which polarization-of-fluorescence measurements could be used to quantitate, for the first time, the degree of spontaneous filament ordering (nematic order parameter) in these F-actin liquid crystals. This order parameter was found to increase monotonically with both filament length and concentration. Actin liquid crystals can readily become distorted by a process known as "texturing." Zigzaging and helicoidal liquid crystalline textures which persisted in the absence of ATP were observed through the polarizing microscope. Possible texturing mechanisms are discussed.
pubmed:grant
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/1330036-12999759, http://linkedlifedata.com/resource/pubmed/commentcorrection/1330036-14454110, http://linkedlifedata.com/resource/pubmed/commentcorrection/1330036-15422102, http://linkedlifedata.com/resource/pubmed/commentcorrection/1330036-1993735, http://linkedlifedata.com/resource/pubmed/commentcorrection/1330036-2015387, http://linkedlifedata.com/resource/pubmed/commentcorrection/1330036-2295647, http://linkedlifedata.com/resource/pubmed/commentcorrection/1330036-2349234, http://linkedlifedata.com/resource/pubmed/commentcorrection/1330036-2377206, http://linkedlifedata.com/resource/pubmed/commentcorrection/1330036-2588005, http://linkedlifedata.com/resource/pubmed/commentcorrection/1330036-2999102, http://linkedlifedata.com/resource/pubmed/commentcorrection/1330036-3219333, http://linkedlifedata.com/resource/pubmed/commentcorrection/1330036-3672117, http://linkedlifedata.com/resource/pubmed/commentcorrection/1330036-4052569, http://linkedlifedata.com/resource/pubmed/commentcorrection/1330036-465454, http://linkedlifedata.com/resource/pubmed/commentcorrection/1330036-4703680, http://linkedlifedata.com/resource/pubmed/commentcorrection/1330036-6313218, http://linkedlifedata.com/resource/pubmed/commentcorrection/1330036-6518259, http://linkedlifedata.com/resource/pubmed/commentcorrection/1330036-6540266
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0006-3495
pubmed:author
pubmed:issnType
Print
pubmed:volume
63
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
794-807
pubmed:dateRevised
2010-9-7
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Quantitation of liquid-crystalline ordering in F-actin solutions.
pubmed:affiliation
Department of Physiology, Tufts University School of Medicine, Boston, Massachusetts.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't