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Development January 1, 2017; 144 (23): 4363-4376.

Mechanical and signaling roles for keratin intermediate filaments in the assembly and morphogenesis of Xenopus mesendoderm tissue at gastrulation.

Sonavane PR , Wang C , Dzamba B , Weber GF , Periasamy A , DeSimone DW .

The coordination of individual cell behaviors is a crucial step in the assembly and morphogenesis of tissues. Xenopus mesendoderm cells migrate collectively along a fibronectin (FN) substrate at gastrulation, but how the adhesive and mechanical forces required for these movements are generated and transmitted is unclear. Traction force microscopy (TFM) was used to establish that traction stresses are limited primarily to leading edge cells in mesendoderm explants, and that these forces are balanced by intercellular stresses in follower rows. This is further reflected in the morphology of these cells, with broad lamellipodial protrusions, mature focal adhesions and a gradient of activated Rac1 evident at the leading edge, while small protrusions, rapid turnover of immature focal adhesions and lack of a Rac1 activity gradient characterize cells in following rows. Depletion of keratin (krt8) with antisense morpholinos results in high traction stresses in follower row cells, misdirected protrusions and the formation of actin stress fibers anchored in streak-like focal adhesions. We propose that maintenance of mechanical integrity in the mesendoderm by keratin intermediate filaments is required to balance stresses within the tissue to regulate collective cell movements.

PubMed ID: 28982683
PMC ID: PMC5769636
Article link: Development
Grant support: [+]

Species referenced: Xenopus
Genes referenced: bcr cad fas fn1 itga5 krt8.1 myl2 pxn rac1
GO keywords: gastrulation [+]
Morpholinos: krt8.1 MO1

Article Images: [+] show captions
References [+] :
Beningo, Nascent focal adhesions are responsible for the generation of strong propulsive forces in migrating fibroblasts. 2001, Pubmed