Caenorhabditis elegans UNC-98, a C2H2 Zn finger protein, is a novel partner of UNC-97/PINCH in muscle adhesion complexes

To further understand the assembly and maintenance of the muscle contractile apparatus, we have identified a new protein, UNC-98, in the muscle of Caenorhabditis elegans. unc-98 mutants display reduced motility and a characteristic defect in muscle structure. We show that the major defect in the mut...

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Bibliographic Details
Published in:Molecular biology of the cell 2003-06, Vol.14 (6), p.2492-2507
Main Authors: Mercer, Kristina B, Flaherty, Denise B, Miller, Rachel K, Qadota, Hiroshi, Tinley, Tina L, Moerman, Donald G, Benian, Guy M
Format: Article
Language:English
Subjects:
Animals
Caenorhabditis elegans - metabolism
Caenorhabditis elegans Proteins - genetics
Caenorhabditis elegans Proteins - metabolism
Cell Adhesion - physiology
Cell Nucleus - metabolism
Cloning, Molecular
DNA-Binding Proteins - metabolism
Muscle Proteins - genetics
Muscle Proteins - metabolism
Muscles - cytology
Muscles - metabolism
Phenotype
Zinc Fingers - genetics
Zinc Fingers - physiology
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Summary:To further understand the assembly and maintenance of the muscle contractile apparatus, we have identified a new protein, UNC-98, in the muscle of Caenorhabditis elegans. unc-98 mutants display reduced motility and a characteristic defect in muscle structure. We show that the major defect in the mutant muscle is in the M-lines and dense bodies (Z-line analogs). Both functionally and compositionally, nematode M-lines and dense bodies are analogous to focal adhesions of nonmuscle cells. UNC-98 is a novel 310-residue polypeptide consisting of four C2H2 Zn fingers and several possible nuclear localization signal and nuclear export signal sequences. By use of UNC-98 antibodies and green fluorescent protein fusions (to full-length UNC-98 and UNC-98 fragments), we have shown that UNC-98 resides at M-lines, muscle cell nuclei, and possibly at dense bodies. Furthermore, we demonstrated that 1) the N-terminal 106 amino acids are both necessary and sufficient for nuclear localization, and 2) the C-terminal (fourth) Zn finger is required for localization to M-lines and dense bodies. UNC-98 interacts with UNC-97, a C. elegans homolog of PINCH. We propose that UNC-98 is both a structural component of muscle focal adhesions and a nuclear protein that influences gene expression.
ISSN:1059-1524
1939-4586
DOI:10.1091/mbc.E02-10-0676