UNC-97/PINCH is involved in the assembly of integrin cell adhesion complexes in Caenorhabditis elegans body wall muscle.
UNC-97/PINCH is an evolutionarily conserved protein that contains five LIM domains and is located at cell-extracellular matrix attachment sites known as cell adhesion complexes. To understand the role of UNC-97/PINCH in cell adhesion, we undertook a combined genetic and cell biological approach to identify the steps required to assemble cell adhesion complexes in Caenorhabditis elegans. First, we have generated a complete loss of function mutation in the unc-97 coding region. unc-97 null mutants arrest development during embryogenesis and reveal that the myofilament lattice and its attachment structures, which include PAT-4/ILK (integrin-linked kinase) and integrin fail to assemble into properly organized arrays. Although in the absence of UNC-97/PINCH, PAT-4/ILK and integrin fail to organize normally, they are capable of colocalizing together at the muscle cell membrane. Alternatively, in integrin and pat-4 mutants, UNC-97/PINCH fails to localize to the muscle cell membrane and instead is found diffusely throughout the muscle cell cytoplasm. In agreement with mammalian studies, we show that LIM domain 1 of UNC-97/PINCH is required for its interaction with PAT-4/ILK in yeast two-hybrid assays. Additionally, we find, by LIM domain deletion analysis, that LIM1 is required for the localization of UNC-97/PINCH to cell adhesion complexes. Our results provide evidence that UNC-97/PINCH is required for the development of C. elegans and is required for the formation of integrin based adhesion structures.
Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4.
Kenneth R
KR
Norman
Shaun
S
Cordes
Hiroshi
H
Qadota
Poupak
P
Rahmani
Donald G
DG
Moerman
D000818:Animals; D017173:Caenorhabditis elegans / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002448:Cell Adhesion / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism*; D016023:Integrins / Q000378:metabolism*; D009124:Muscle Proteins / Q000235:genetics / Q000502:physiology*; D009132:Muscles / Q000378:metabolism; D009154:Mutation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D017434:Protein Structure, Tertiary; D014157:Transcription Factors / Q000378:metabolism; D000099200:Scaffold Protein ILK
D029742:Caenorhabditis elegans Proteins; D016023:Integrins; D009124:Muscle Proteins; D017346:Protein Serine-Threonine Kinases; D014157:Transcription Factors; C117451:UNC-97 protein, C elegans; C466238:PAT-4 protein, C elegans; D000099200:Scaffold Protein ILK