Universität zu Köln

Polster, Alexander, Perni, Stefano ORCID: 0000-0002-0591-4376, Filipova, Dilyana, Moua, Ong, Ohrtman, Joshua D., Bichraoui, Hicham, Beam, Kurt G. and Papadopoulos, Symeon (2018). Junctional trafficking and restoration of retrograde signaling by the cytoplasmic RyR1 domain. J. Gen. Physiol., 150 (2). S. 293 - 307. NEW YORK: ROCKEFELLER UNIV PRESS. ISSN 1540-7748

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Abstract

The type 1 ryanodine receptor (RyR1) in skeletal muscle is a homotetrameric protein that releases Ca2+ from the sarcoplasmic reticulum (SR) in response to an orthograde signal from the dihydropyridine receptor (DHPR) in the plasma membrane (PM). Additionally, a retrograde signal from RyR1 increases the amplitude of the Ca2+ current produced by Ca(v)1.1, the principle subunit of the DHPR. This bidirectional signaling is thought to depend on physical links, of unknown identity, between the DHPR and RyR1. Here, we investigate whether the isolated cytoplasmic domain of RyR1 can interact structurally or functionally with Ca(v)1.1 by producing an N-terminal construct (RyR1(1)(:)(4300)) that lacks the C-terminal membrane domain. In Ca(v)1.1-null (dysgenic) myotubes, RyR1(1)(:)(4300) is diffusely distributed, but in RyR1-null (dyspedic) myotubes it localizes in puncta at SR-PM junctions containing endogenous Ca(v)1.1. Fluorescence recovery after photobleaching indicates that diffuse RyR1(1)(:)(4300) is mobile, whereas resistance to being washed out with a large-bore micropipette indicates that the punctate RyR1(1)(:)(4300) stably associates with PM-SR junctions. Strikingly, expression of RyR1(1)(:)(4300) in dyspedic myotubes causes an increased amplitude, and slowed activation, of Ca2+ current through Ca(v)1.1, which is almost identical to the effects of full-length RyR1. Fast protein liquid chromatography indicates that similar to 25% of RyR1(1)(:)(4300) in diluted cytosolic lysate of transfected tsA201 cells is present in complexes larger in size than the monomer, and intermolecular fluorescence resonance energy transfer implies that RyR1(1)(:)(4300) is significantly oligomerized within intact tsA201 cells and dyspedic myotubes. A large fraction of these oligomers may be homotetramers because freeze-fracture electron micrographs reveal that the frequency of particles arranged like DH PR tetrads is substantially increased by transfecting RyR-null myotubes with RyR1(1)(:)(4300) . In summary, the RyR1 cytoplasmic domain, separated from its SR membrane anchor, retains a tendency toward oligomerization/tetramerization, binds to SR-PM junctions in myotubes only if Ca(v)1.1 is also present and is fully functional in retrograde signaling to Ca(v)1.1.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Polster, Alexander UNSPECIFIED UNSPECIFIED UNSPECIFIED Perni, Stefano UNSPECIFIED orcid.org/0000-0002-0591-4376 UNSPECIFIED Filipova, Dilyana UNSPECIFIED UNSPECIFIED UNSPECIFIED Moua, Ong UNSPECIFIED UNSPECIFIED UNSPECIFIED Ohrtman, Joshua D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Bichraoui, Hicham UNSPECIFIED UNSPECIFIED UNSPECIFIED Beam, Kurt G. UNSPECIFIED UNSPECIFIED UNSPECIFIED Papadopoulos, Symeon UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-197391
DOI:	10.1085/jgp.201711879
Journal or Publication Title:	J. Gen. Physiol.
Volume:	150
Number:	2
Page Range:	S. 293 - 307
Date:	2018
Publisher:	ROCKEFELLER UNIV PRESS
Place of Publication:	NEW YORK
ISSN:	1540-7748
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language RYANODINE RECEPTOR PROTEIN; GREEN FLUORESCENT PROTEIN; COUPLED CALCIUM-ENTRY; MOUSE SKELETAL-MUSCLE; DIHYDROPYRIDINE-RECEPTOR; CA2+ CHANNEL; COMPLEMENTARY-DNA; CONTRACTION; TETRADS; OLIGOMERIZATION Multiple languages Physiology Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/19739