Muscle Activity and Muscle Agrin Regulate the Organization of Cytoskeletal Proteins and Attached Acetylcholine Receptor (Achr) Aggregates in Skeletal Muscle Fibers

In innervated skeletal muscle fibers, dystrophin and β-dystroglycan form rib-like structures (costameres) that appear as predominantly transverse stripes over Z and M lines. Here, we show that the orientation of these stripes becomes longitudinal in denervated muscles and transverse again in denerva...

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Main Authors:	Bezakova, Gabriela, Lømo, Terje
Format:	Online
Language:	English
Published:	The Rockefeller University Press 2001
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2150728/

id	pubmed-2150728
recordtype	oai_dc
spelling	pubmed-21507282008-05-01 Muscle Activity and Muscle Agrin Regulate the Organization of Cytoskeletal Proteins and Attached Acetylcholine Receptor (Achr) Aggregates in Skeletal Muscle Fibers Bezakova, Gabriela Lømo, Terje Original Article In innervated skeletal muscle fibers, dystrophin and β-dystroglycan form rib-like structures (costameres) that appear as predominantly transverse stripes over Z and M lines. Here, we show that the orientation of these stripes becomes longitudinal in denervated muscles and transverse again in denervated electrically stimulated muscles. Skeletal muscle fibers express nonneural (muscle) agrin whose function is not well understood. In this work, a single application of ≥10 nM purified recombinant muscle agrin into denervated muscles preserved the transverse orientation of costameric proteins that is typical for innervated muscles, as did a single application of ≥1 μM neural agrin. At lower concentration, neural agrin induced acetylcholine receptor aggregates, which colocalized with longitudinally oriented β-dystroglycan, dystrophin, utrophin, syntrophin, rapsyn, and β2-laminin in denervated unstimulated fibers and with the same but transversely oriented proteins in innervated or denervated stimulated fibers. The results indicate that costameres are plastic structures whose organization depends on electrical muscle activity and/or muscle agrin. The Rockefeller University Press 2001-06-25 /pmc/articles/PMC2150728/ /pubmed/11425875 Text en © 2001 The Rockefeller University Press This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Bezakova, Gabriela Lømo, Terje
spellingShingle	Bezakova, Gabriela Lømo, Terje Muscle Activity and Muscle Agrin Regulate the Organization of Cytoskeletal Proteins and Attached Acetylcholine Receptor (Achr) Aggregates in Skeletal Muscle Fibers
author_facet	Bezakova, Gabriela Lømo, Terje
author_sort	Bezakova, Gabriela
title	Muscle Activity and Muscle Agrin Regulate the Organization of Cytoskeletal Proteins and Attached Acetylcholine Receptor (Achr) Aggregates in Skeletal Muscle Fibers
title_short	Muscle Activity and Muscle Agrin Regulate the Organization of Cytoskeletal Proteins and Attached Acetylcholine Receptor (Achr) Aggregates in Skeletal Muscle Fibers
title_full	Muscle Activity and Muscle Agrin Regulate the Organization of Cytoskeletal Proteins and Attached Acetylcholine Receptor (Achr) Aggregates in Skeletal Muscle Fibers
title_fullStr	Muscle Activity and Muscle Agrin Regulate the Organization of Cytoskeletal Proteins and Attached Acetylcholine Receptor (Achr) Aggregates in Skeletal Muscle Fibers
title_full_unstemmed	Muscle Activity and Muscle Agrin Regulate the Organization of Cytoskeletal Proteins and Attached Acetylcholine Receptor (Achr) Aggregates in Skeletal Muscle Fibers
title_sort	muscle activity and muscle agrin regulate the organization of cytoskeletal proteins and attached acetylcholine receptor (achr) aggregates in skeletal muscle fibers
description	In innervated skeletal muscle fibers, dystrophin and β-dystroglycan form rib-like structures (costameres) that appear as predominantly transverse stripes over Z and M lines. Here, we show that the orientation of these stripes becomes longitudinal in denervated muscles and transverse again in denervated electrically stimulated muscles. Skeletal muscle fibers express nonneural (muscle) agrin whose function is not well understood. In this work, a single application of ≥10 nM purified recombinant muscle agrin into denervated muscles preserved the transverse orientation of costameric proteins that is typical for innervated muscles, as did a single application of ≥1 μM neural agrin. At lower concentration, neural agrin induced acetylcholine receptor aggregates, which colocalized with longitudinally oriented β-dystroglycan, dystrophin, utrophin, syntrophin, rapsyn, and β2-laminin in denervated unstimulated fibers and with the same but transversely oriented proteins in innervated or denervated stimulated fibers. The results indicate that costameres are plastic structures whose organization depends on electrical muscle activity and/or muscle agrin.
publisher	The Rockefeller University Press
publishDate	2001
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2150728/
_version_	1611423915852169216

Muscle Activity and Muscle Agrin Regulate the Organization of Cytoskeletal Proteins and Attached Acetylcholine Receptor (Achr) Aggregates in Skeletal Muscle Fibers

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