TY - JOUR
T1 - Rsu1 contributes to regulation of cell adhesion and spreading by PINCH1-dependent and - Independent mechanisms
AU - Gonzalez-Nieves, Reyda
AU - Desantis, Akiko Iwahari
AU - Cutler, Mary L.
N1 - Funding Information:
Acknowledgments The authors would like to acknowledge the technical assistance of Laurelis Santiago and helpful discussion from members of the laboratory. The expert advice on endocytosis from Drs. Gudrun Ihrke and Michael Schell and reagents provided by them for those assays were much appreciated. The authors are grateful to Dr. Jim Bear for providing the anti-coronin antibody. The following funding agencies provided support: Congressionally Directed Medical Research Program grant W81XWH-09-2-0056 from the Wound Healing Program (to MLC), grant from the Murtha Cancer Center (to MLC) and W81XWH-10-1-0024 from the Congressionally Directed Medical Research Breast Cancer Program (predoctoral fellowship to RG-N).
PY - 2013/12
Y1 - 2013/12
N2 - Cell adhesion and migration are complex processes that require integrin activation, the formation and dissolution of focal adhesion (FAs), and linkage of actin cytoskeleton to the FAs. The IPP (ILK, PINCH, Parvin) complex regulates FA formation via binding of the adaptor protein ILK to β1 integrin, PINCH and parvin. The signaling protein Rsu1 is linked to the complex via binding PINCH1. The role of Rsu1 and PINCH1 in adhesion and migration was examined in non-transformed mammary epithelial cells. Confocal microscopy revealed that the depletion of either Rsu1 or PINCH1 by siRNA in MCF10A cells decreased the number of focal adhesions and altered the distribution and localization of β1 integrin, vinculin, talin and paxillin without affecting the levels of FA protein expression. This correlated with reduced adhesion, failure to spread or migrate in response to EGF and a loss of actin stress fibers and caveolae. In addition, constitutive phosphorylation of actin regulatory proteins occurred in the absence of PINCH1. The depletion of Rsu1 caused significant reduction in PINCH1 implying that Rsu1 may function by regulating levels of PINCH1. However, while both Rsu1- or PINCH1-depleted cells retained the ability to activate adhesion signaling in response to EGF stimulation, only Rsu1 was required for EGF-induced p38 Map Kinase phosphorylation and ATF2 activation, suggesting an Rsu1 function independent from the IPP complex. Reconstitution of Rsu1-depleted cells with an Rsu1 mutant that does not bind to PINCH1 failed to restore FAs or migration but did promote spreading and constitutive p38 activation. These data show that Rsu1-PINCH1 association with ILK and the IPP complex is required for regulation of adhesion and migration but that Rsu1 has a critical role in linking integrin-induced adhesion to activation of p38 Map kinase signaling and cell spreading. Moreover, it suggests that Rsu1 may regulate p38 signaling from the IPP complex affecting other functions including survival.
AB - Cell adhesion and migration are complex processes that require integrin activation, the formation and dissolution of focal adhesion (FAs), and linkage of actin cytoskeleton to the FAs. The IPP (ILK, PINCH, Parvin) complex regulates FA formation via binding of the adaptor protein ILK to β1 integrin, PINCH and parvin. The signaling protein Rsu1 is linked to the complex via binding PINCH1. The role of Rsu1 and PINCH1 in adhesion and migration was examined in non-transformed mammary epithelial cells. Confocal microscopy revealed that the depletion of either Rsu1 or PINCH1 by siRNA in MCF10A cells decreased the number of focal adhesions and altered the distribution and localization of β1 integrin, vinculin, talin and paxillin without affecting the levels of FA protein expression. This correlated with reduced adhesion, failure to spread or migrate in response to EGF and a loss of actin stress fibers and caveolae. In addition, constitutive phosphorylation of actin regulatory proteins occurred in the absence of PINCH1. The depletion of Rsu1 caused significant reduction in PINCH1 implying that Rsu1 may function by regulating levels of PINCH1. However, while both Rsu1- or PINCH1-depleted cells retained the ability to activate adhesion signaling in response to EGF stimulation, only Rsu1 was required for EGF-induced p38 Map Kinase phosphorylation and ATF2 activation, suggesting an Rsu1 function independent from the IPP complex. Reconstitution of Rsu1-depleted cells with an Rsu1 mutant that does not bind to PINCH1 failed to restore FAs or migration but did promote spreading and constitutive p38 activation. These data show that Rsu1-PINCH1 association with ILK and the IPP complex is required for regulation of adhesion and migration but that Rsu1 has a critical role in linking integrin-induced adhesion to activation of p38 Map kinase signaling and cell spreading. Moreover, it suggests that Rsu1 may regulate p38 signaling from the IPP complex affecting other functions including survival.
KW - Cell adhesion
KW - Cell migration
KW - PINCH1
KW - Rsu1
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UR - http://www.scopus.com/inward/citedby.url?scp=84891373061&partnerID=8YFLogxK
U2 - 10.1007/s12079-013-0207-5
DO - 10.1007/s12079-013-0207-5
M3 - Article
AN - SCOPUS:84891373061
SN - 1873-9601
VL - 7
SP - 279
EP - 293
JO - Journal of Cell Communication and Signaling
JF - Journal of Cell Communication and Signaling
IS - 4
ER -