Large Isoforms of UNC-89 (Obscurin) Are Required for Muscle Cell Architecture and Optimal Calcium Release in Caenorhabditis elegans

• Type of Material: Article
• Authors: Patrick M. Spooner, Albany Medical College; Jennifer Bonner, Albany Medical College; Andres V. Maricq, University of Utah; Guy Benian, Emory University; Kenneth R. Norman, Albany Medical College
• Language: English
• Date: 2012-07-02
• Publisher: Public Library of Science
• Publication Version: Final Published Version
• Copyright Statement: © 2012 Spooner et al.
• License: Creative Commons Attribution 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.1371/journal.pone.0040182
• Title of Journal or Parent Work: PLoS ONE
• ISSN: 1932-6203
• Volume: 7
• Issue: 7
• Start Page: e40182
• End Page: e40182
• Grant/Funding Information: This work was supported by the American Heart Association (www.heart.org), the Alzheimer's Association (www.alz.org), and National Institutes of Health grant GM088213 (www.nigms.nih.gov) to KRN, and NIH grant AR051466 (www.niams.nih.gov) to GMB.
• Keywords: STRIATED-MUSCLES; Multidisciplinary Sciences; BODY-WALL MUSCLE; CA2+; SARCOPLASMIC-RETICULUM; Calcium signaling; Caenorhabditis elegans; ORGANIZATION; Biological locomotion; Sarcomeres; SKELETAL-MUSCLE; Science & Technology; Muscle contraction; Myofilaments; Muscle proteins; RNA interference; LOCALIZATION
• Research Categories: Health Sciences, Pathology; Biology, Cell

Abstract

Calcium, a ubiquitous intracellular signaling molecule, controls a diverse array of cellular processes. Consequently, cells have developed strategies to modulate the shape of calcium signals in space and time. The force generating machinery in muscle is regulated by the influx and efflux of calcium ions into the muscle cytoplasm. In order for efficient and effective muscle contraction to occur, calcium needs to be rapidly, accurately and reliably regulated. The mechanisms underlying this highly regulated process are not fully understood. Here, we show that the Caenorhabditis elegans homolog of the giant muscle protein obscurin, UNC-89, is required for normal muscle cell architecture. The large immunoglobulin domain-rich isoforms of UNC-89 are critical for sarcomere and sarcoplasmic reticulum organization. Furthermore, we have found evidence that this structural organization is crucial for excitation-contraction coupling in the body wall muscle, through the coordination of calcium signaling. Thus, our data implicates UNC-89 in maintaining muscle cell architecture and that this precise organization is essential for optimal calcium mobilization and efficient and effective muscle contraction.