Defining actin filament length in striated muscle: Rulers and caps or dynamic stability?

Citation
R. Littlefield et Vm. Fowler, Defining actin filament length in striated muscle: Rulers and caps or dynamic stability?, ANN R C DEV, 14, 1998, pp. 487-525
Citations number
194
Language
INGLESE
art.tipo
Review
Categorie Soggetti
Cell & Developmental Biology
Journal title
ANNUAL REVIEW OF CELL AND DEVELOPMENTAL BIOLOGY
ISSN journal
1081-0706 → ACNP
Volume
14
Year of publication
1998
Pages
487 - 525
Database
ISI
SICI code
1081-0706(1998)14:<487:DAFLIS>2.0.ZU;2-D
Abstract
Actin filaments (thin filaments) are polymerized to strikingly uniform leng ths in striated muscle sarcomeres. Yet, actin monomers can exchange dynamic ally into thin filaments in vivo, indicating that actin monomer association and dissociation at filament ends must be highly regulated to maintain the uniformity of filament lengths. We propose several hypothetical mechanisms that could generate uniform actin filament length distributions and discus s their application to the determination of thin filament length in vivo. A t the Z line, titin may determine the minimum extent and tropomyosin the ma ximum extent of thin filament overlap by regulating a-actinin binding to ac tin, while a unique Z filament may bind to capZ and regulate barbed end cap ping. For the free portion of the thin filament, we evaluate possibilities that thin filament components (e.g. nebulin or the tropomyosin/troponin pol ymer) determine thin filament lengths by binding directly to tropomodulin a nd regulating pointed end capping, or alternatively that myosin thick filam ents, together with titin, determine filament length by indirectly regulati ng tropomodulin's capping activity.