RT Journal Article
SR Electronic
T1 RhoA effectors LOK/SLK activate ERM proteins to locally inhibit RhoA and define apical morphology
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2020.07.02.185298
DO 10.1101/2020.07.02.185298
A1 Riasat Zaman
A1 Andrew Lombardo
A1 Cécile Sauvanet
A1 Raghuvir Viswanatha
A1 Valerie Awad
A1 Locke Ezra-Ros Bonomo
A1 David McDermitt
A1 Anthony Bretscher
YR 2020
UL http://biorxiv.org/content/early/2020/07/27/2020.07.02.185298.abstract
AB Activated Ezrin-Radixin-Moesin (ERM) proteins link the plasma membrane to the actin cytoskeleton to generate apical structures, including microvilli. Among many kinases implicated in ERM activation are the homologs LOK and SLK. CRISPR/Cas9 was used to knockout all ERM proteins or LOK/SLK in human cells. LOK/SLK knockout eliminates all ERM activating phosphorylation. The apical domain of cells lacking LOK/SLK or ERMs is strikingly similar and selectively altered, with loss of microvill, and junctional actin replaced by ectopic myosin-II containing apical stress-fiber-like structures. Constitutively active ezrin can reverse the phenotypes of either ERMs or LOK/SLK knockouts, showing that the major function of LOK/SLK is to activate ERMs. Both knockout lines have elevated active RhoA with concomitant enhanced myosin light chain phosphorylation, revealing that active ERMs are negative regulators of RhoA. As RhoA-GTP activates LOK/SLK to activate ERM proteins, the ability of active ERMs to negatively regulate RhoA-GTP represents a novel local feedback loop necessary for the proper apical morphology of epithelial cells.Competing Interest StatementThe authors have declared no competing interest.