Concentric intermediate filament lattice links to specialized Z-band junctional complexes in sonic muscle fibers of the type I male midshipman fish.

Published

Journal Article

Type I male midshipman fish produce high-frequency hums for prolonged durations using sonic muscle fibers, each of which contains a hollow tube of radially oriented thin and flat myofibrils that display extraordinarily wide ( approximately 1.2 microm) Z bands. We have revealed an elaborate cytoskeletal network of desmin filaments associated with the contractile cylinder that form interconnected concentric ring structures in the core and periphery at the level of the Z bands. Stretch and release of single fibers revealed reversible length changes in the elastic desmin lattice. This lattice is linked to Z bands via novel intracellular desmosome-like junctional complexes that collectively form a ring, termed the "Z corset," around the periphery and within the core of the cylinder. The junctional complex consists of regularly spaced parallel approximately 900-nm-long cytoskeletal rods, or "Z bars," interconnected with slender (3-4 nm) plectin-positive filaments. Z bars are linked to the Z band by plectin filaments and on the opposite side to a dense mesh of desmin filaments. Adjacent Z bands are linked by slender filaments that appear to suspend sarcotubules. We propose that the highly reinforced elastic desmin cytoskeleton and the unique Z band junctions are structural adaptations that enable the muscles' high-frequency and high-endurance activity.

Full Text

Cited Authors

  • Lewis, MK; Nahirney, PC; Chen, V; Adhikari, BB; Wright, J; Reedy, MK; Bass, AH; Wang, K

Published Date

  • July 2003

Published In

Volume / Issue

  • 143 / 1

Start / End Page

  • 56 - 71

PubMed ID

  • 12892726

Pubmed Central ID

  • 12892726

International Standard Serial Number (ISSN)

  • 1047-8477

Language

  • eng

Conference Location

  • United States