title: Two LIM domain proteins and UNC-96 link UNC-97/pinch to myosin thick filaments in Caenorhabditis elegans muscle.
abstract: By yeast two-hybrid screening, we found three novel interactors (UNC-95, LIM-8, and LIM-9) for UNC-97/PINCH in Caenorhabditis elegans. All three proteins contain LIM domains that are required for binding. Among the three interactors, LIM-8 and LIM-9 also bind to UNC-96, a component of sarcomeric M-lines. UNC-96 and LIM-8 also bind to the C-terminal portion of a myosin heavy chain (MHC), MHC A, which resides in the middle of thick filaments in the proximity of M-lines. All interactions identified by yeast two-hybrid assays were confirmed by in vitro binding assays using purified proteins. All three novel UNC-97 interactors are expressed in body wall muscle and by antibodies localize to M-lines. Either a decreased or an increased dosage of UNC-96 results in disorganization of thick filaments. Our previous studies showed that UNC-98, a C2H2 Zn finger protein, acts as a linkage between UNC-97, an integrin-associated protein, and MHC A in myosin thick filaments. In this study, we demonstrate another mechanism by which this linkage occurs: from UNC-97 through LIM-8 or LIM-9/UNC-96 to myosin.
authors.affiliation: Department of Pathology, Emory University, Atlanta, GA 30322, USA.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Qadota
authors.forename: Kristina B
authors.initials: KB
authors.lastname: Mercer
authors.forename: Rachel K
authors.initials: RK
authors.lastname: Miller
authors.forename: Kozo
authors.initials: K
authors.lastname: Kaibuchi
authors.forename: Guy M
authors.initials: GM
authors.lastname: Benian
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism; D005786:Gene Expression Regulation; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D060588:LIM Domain Proteins; D009124:Muscle Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D009132:Muscles / Q000378:metabolism*; D009218:Myosins / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding
chemical_list: D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D018398:Homeodomain Proteins; D060588:LIM Domain Proteins; C525961:Lim-8 protein, C elegans; C525958:Lim-9 protein, C elegans; D009124:Muscle Proteins; C514106:UNC-96 protein, C elegans; C117451:UNC-97 protein, C elegans; D009218:Myosins