Annexin 2 regulates intestinal epithelial cell spreading and wound closure through Rho-related signaling.
Epithelial cell migration is a critical event in gastrointestinal mucosal wound healing and is dependent on actin cytoskeletal reorganization. We observed increased expression of an actin regulatory protein, annexin 2, in migrating intestinal epithelial cells. Small interfering RNA (siRNA)-mediated knockdown of annexin 2 expression in Caco-2 epithelial cells resulted in significant reductions in cell spreading and wound closure associated with decreased formation of filamentous actin bundles along the base of migrating cells. Because annexin 2 has been shown to influences actin cytoskeletal remodeling through targeting signaling molecules to membrane domains, we examined the membrane association and activation status of Rho GTPases after annexin 2 knockdown. We observed Rho dissociation from membranes and decreased Rho activity following annexin 2 siRNA transfection. Inhibition of cell spreading and wound closure in annexin 2 siRNA-transfected cells was prevented by expression of constitutively active RhoA. Rho colocalized with annexin 2 in lamellipodia and along the cytoplasmic face of the plasma membrane. In addition, annexin 2 was observed to co-immunoprecipitate with endogenous Rho and constitutively active RhoA. These findings suggest that annexin 2 plays a role in targeting Rho to cellular membranes, thereby modulating Rho-related signaling events regulating cytoskeletal reorganization during epithelial cell migration.
Babbin
Brian A
BA
Epithelial Pathobiology Research Unit, Department of Pathology and Laboratory Medicine, Emory University, Atlanta, Georgia 30322, USA. bbabbin@emory.edu
Parkos
Charles A
CA
Mandell
Kenneth J
KJ
Winfree
L Matthew
LM
Laur
Oskar
O
Ivanov
Andrei I
AI
Nusrat
Asma
A
D000199:Actins / Q000378:metabolism; D017306:Annexin A2 / Q000378:metabolism*; D018938:Caco-2 Cells; D002465:Cell Movement / Q000502:physiology*; D004847:Epithelial Cells / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006801:Humans; D007091:Image Processing, Computer-Assisted; D015151:Immunoblotting; D047468:Immunoprecipitation; D007413:Intestinal Mucosa / Q000378:metabolism*; D018613:Microscopy, Confocal; D020411:Oligonucleotide Array Sequence Analysis; D034741:RNA, Small Interfering; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology*; D014162:Transfection; D014945:Wound Healing / Q000502:physiology*; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
C472822:ANXA2 protein, human; D000199:Actins; D017306:Annexin A2; D034741:RNA, Small Interfering; D020742:rhoA GTP-Binding Protein