CORO7 functions as a scaffold protein for the core kinase complex assembly of the Hippo pathway

Jina Park,Kyoungho Jun,Yujin Choi,Eunju Yoon,Wonho Kim,Yoon-Gu Jang,Jongkyeong Chung

doi:10.1074/jbc.ra120.013297

Abstract

The Hippo pathway controls organ size and tissue homeostasis through the regulation of cell proliferation and apoptosis. However, the exact molecular mechanisms underpinning Hippo pathway regulation are not fully understood. Here, we identify a new component of the Hippo pathway: coronin 7 (CORO7), a coronin protein family member that is involved in organization of the actin cytoskeleton. pod1, the Drosophila ortholog of CORO7, genetically interacts with key Hippo pathway genes in Drosophila. In mammalian cells, CORO7 is required for the activation of the Hippo pathway in response to cell–cell contact, serum deprivation, and cytoskeleton damage. CORO7 forms a complex with the core components of the pathway and functions as a scaffold for the Hippo core kinase complex. Collectively, these results demonstrate that CORO7 is a key scaffold controlling the Hippo pathway via modulating protein–protein interactions.

Highlights

Remain unclear [2, 13]
After finding genetic interactions between pod1 and Hippo pathway genes in Drosophila, we demonstrated that its ortholog Coronin 7 (CORO7) is required for the activation of the pathway in mammalian cells
We showed that overexpressing Pod1 suppresses the phenotypes induced by knocking down Hpo or overexpressing Yki in wings and eyes of Drosophila, whereas yes-associated protein (YAP) inhibition induced by various stimuli activating the Hippo pathway is repressed on CORO7 depletion in mammalian cells

Summary

Results

To identify new regulators of the Hippo signaling pathway, we listed Drosophila genes that have been reported to interact with the components of the pathway from multiple interactome databases, including BioGRID, BioPlex, STRING, and DroID (Table S1), and conducted a genetic screen by knocking down or overexpressing each gene. These data suggested that CORO7 acts as a scaffold for LATS1, helping it to interact with SAV1 and MST2 This result was further corroborated by observing a decreased binding of endogenous LATS1 and SAV1 to overexpressed MST2 on CORO7 knockdown (Fig. 4C and Fig. S5E). CORO7, coronin 7; FBM, FERM-binding motif; HA, hemagglutinin; LATS1, large tumor suppressor kinase 1/2; MOB1, MOB kinase activator 1; MST2, mammalian sterile 20-like kinase 2; SARAH, Sav/ Rassf/Hpo; SAV1, salvador family WW domain–containing protein 1; WCL, whole cell lysate. When the Hippo pathway was activated by serum starvation or LatB-induced actin depolymerization, levels of SAV1 and MST2 that were coimmunoprecipitated with CORO7 decreased significantly (Fig. 5A and Fig. S6, A and C), whereas LATS1–CORO7 binding was not affected by the serum deprivation (Fig. S6B). These data collectively implicate a possible role of Src in regulating CORO7

Discussion

Findings

Experimental procedures