CSN-5, a component of the COP9 signalosome complex, regulates the levels of UNC-96 and UNC-98, two components of M-lines in Caenorhabditis elegans muscle.
In Caenorhabditis elegans two M-line proteins, UNC-98 and UNC-96, are involved in myofibril assembly and/or maintenance, especially myosin thick filaments. We found that CSN-5, a component of the COP9 signalosome complex, binds to UNC-98 and -96 using the yeast two-hybrid method. These interactions were confirmed by biochemical methods. The CSN-5 protein contains a Mov34 domain. Although one other COP9 signalosome component, CSN-6, also has a Mov34 domain, CSN-6 did not interact with UNC-98 or -96. Anti-CSN-5 antibody colocalized with paramyosin at A-bands in wild type and colocalized with abnormal accumulations of paramyosin found in unc-98, -96, and -15 (encodes paramyosin) mutants. Double knockdown of csn-5 and -6 could slightly suppress the unc-96 mutant phenotype. In the double knockdown of csn-5 and -6, the levels of UNC-98 protein were increased and the levels of UNC-96 protein levels were slightly reduced, suggesting that CSN-5 promotes the degradation of UNC-98 and that CSN-5 stabilizes UNC-96. In unc-15 and unc-96 mutants, CSN-5 protein was reduced, implying the existence of feed back regulation from myofibril proteins to CSN-5 protein levels. Taken together, we found that CSN-5 functions in muscle cells to regulate UNC-98 and -96, two M-line proteins.
Miller
Rachel K
RK
Department of Pathology, Emory University, Atlanta, GA 30322, USA.
Qadota
Hiroshi
H
Stark
Thomas J
TJ
Mercer
Kristina B
KB
Wortham
Tesheka S
TS
Anyanful
Akwasi
A
Benian
Guy M
GM
D015153:Blotting, Western; D000075686:COP9 Signalosome Complex; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism*; D009132:Muscles / Q000378:metabolism*; D009154:Mutation; D010447:Peptide Hydrolases / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D034622:RNA Interference; D014335:Tropomyosin / Q000235:genetics / Q000378:metabolism; D020798:Two-Hybrid System Techniques
C524498:CSN-5 protein, C elegans; D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D046912:Multiprotein Complexes; D009124:Muscle Proteins; D014335:Tropomyosin; C509308:UNC-15 protein, C elegans; C514106:UNC-96 protein, C elegans; C481656:UNC-98 protein, C elegans; D010447:Peptide Hydrolases; D000075686:COP9 Signalosome Complex