PINCH1 regulates cell-matrix and cell-cell adhesions, cell polarity and cell survival during the peri-implantation stage.
PINCH1 is composed of 5 LIM domains, binds integrin-linked kinase (ILK) and locates to integrin-mediated adhesion sites. In order to investigate PINCH1 function we generated mice and embryonic stem (ES) cell-derived embryoid bodies (EBs) lacking the PINCH1 gene. Similar to mice lacking beta1 integrin or Ilk, loss of PINCH1 arrested development at the peri-implantation stage. In contrast to beta1 integrin or Ilk mutants, however, disruption of the PINCH1 gene produced implantation chambers with visible cell clumps even at embryonic day 9.5. In order to define the phenotype leading to the peri-implantation lethality we made PINCH1-null EBs and found similar but also additional defects not observed in beta1 integrin or Ilk mutant EBs. The similarities included abnormal epiblast polarity, impaired cavitation and detachment of endoderm and epiblast from basement membranes. Additional defects, which were not observed in beta1 integrin- or ILK-deficient mice or EBs, included abnormal cell-cell adhesion of endoderm and epiblast as well as the presence of apoptotic cells in the endodermal cell layer. Although ILK and PINCH1 were shown to be involved in the phosphorylation of serine-473 of PKB/Akt, immunostaining with specific antibodies revealed no apparent alteration of PKB/Akt phosphorylation in PINCH1-deficient EBs. Altogether these data demonstrate an important role of PINCH1 for integrin function, actin organization, cell-cell adhesion and endodermal cell survival during the implanting of mouse embryos.
Department of Pathology and Medicine, Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA.
Shaohua
S
Li
Randi
R
Bordoy
Fabio
F
Stanchi
Markus
M
Moser
Attila
A
Braun
Oliver
O
Kudlacek
Ulla M
UM
Wewer
Peter D
PD
Yurchenco
Reinhard
R
Fässler
D000199:Actins / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D017209:Apoptosis / Q000502:physiology; D002448:Cell Adhesion / Q000502:physiology*; D016764:Cell Polarity / Q000502:physiology*; D002470:Cell Survival / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D010064:Embryo Implantation / Q000502:physiology*; D004622:Embryo, Mammalian / Q000196:embryology / Q000378:metabolism; D005109:Extracellular Matrix / Q000502:physiology* / Q000648:ultrastructure; D060588:LIM Domain Proteins; D008565:Membrane Proteins; D051379:Mice; D008969:Molecular Sequence Data; D019108:Tight Junctions / Q000502:physiology
D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D004268:DNA-Binding Proteins; D060588:LIM Domain Proteins; C490232:Lims1 protein, mouse; C490234:Lims2 protein, mouse; D008565:Membrane Proteins