RT Journal Article
SR Electronic
T1 Superresolution architecture of pluripotency guarding adhesions
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 402305
DO 10.1101/402305
A1 Aki Stubb
A1 Camilo Guzmán
A1 Elisa Närvä
A1 Jesse Aaron
A1 Teng-Leong Chew
A1 Markku Saari
A1 Mitro Miihkinen
A1 Guillaume Jacquemet
A1 Johanna Ivaska
YR 2018
UL http://biorxiv.org/content/early/2018/08/28/402305.abstract
AB Human pluripotent stem cells (hPSC) can generate almost all adult cell lineages. While it is clear that key transcriptional programmes are important elements for maintaining pluripotency, the equally essential requirement for cell adhesion to specific extracellular matrix components remains poorly defined. Our recent observation that hPSC colonies form unusually large “cornerstone” focal adhesions (FA), distinct from parental somatic cells, that are lost following differentiation, emphasises the potential of these atypical FA as gatekeepers of pluripotency. Here, using nanopatterns, we further demonstrate that physical restriction of adhesion size, in hPSC colonies, is sufficient to trigger differentiation. Using superresolution two-colour interferometric photo-activated localization microscopy (iPALM), we examined the three-dimensional architecture of these cornerstone adhesions and report vertical lamination of FA proteins with three main structural peculiarities: 1) integrin β5 and talin are present at high density, at the edges of cornerstone FA, adjacent to a vertical kank-rich protein wall. 2) Vinculin localises higher than expected with respect to the substrata, and 3) surprisingly, actin and α-actinin are present in two discrete layers, a previously undescribed localisation for these proteins. Finally, we report that depletion of kanks diminishes FA patterning, and actin organisation within the colony, indicating a key role for kanks in hPSC colony architecture.