Identification of myosin II as a cripto binding protein and regulator of cripto function in stem cells and tissue regeneration

Abstract

Cripto regulates stem cell function in normal and disease contexts via TGFbeta/activin/nodal, PI3K/Akt, MAPK and Wnt signaling. Still, the molecular mechanisms that govern these pleiotropic functions of Cripto remain poorly understood. We performed an unbiased screen for novel Cripto binding proteins using proteomics-based methods, and identified novel proteins including members of myosin II complexes, the actin cytoskeleton, the cellular stress response, and extracellular exosomes. We report that myosin II, and upstream ROCK1/2 activities are required for localization of Cripto to cytoplasm/membrane domains and its subsequent release into the conditioned media fraction of cultured cells. Functionally, we demonstrate that soluble Cripto (one-eyed pinhead in zebrafish) promotes proliferation in mesenchymal stem cells (MSCs) and stem cell-mediated wound healing in the zebrafish caudal fin model of regeneration. Notably, we demonstrate that both Cripto and myosin II inhibitors attenuated regeneration to a similar degree and in a non-additive manner. Taken together, our data present a novel role for myosin II function in regulating subcellular Cripto localization and function in stem cells and an important regulatory mechanism of tissue regeneration. Importantly, these insights may further the development of context-dependent Cripto agonists and antagonists for therapeutic benefit.

CRIPTO antagonist ALK4L75A-Fc inhibits breast cancer cell plasticity and adaptation to stress

“…In a notable example of this, Wicha and colleagues showed that certain stem cell populations (i.e., ALDH+ cells) reside in stressed tumor microdomains and increase following antiangiogenic, hypoxia-inducing therapy (Avastin) [52]. It remains to be determined if other critical cell processes like metabolism or trafficking, which may also be under CRIPTO control [53,54], are critical contributors to overall cellular plasticity and adaptability.…”

Glucocorticoid receptor-dependent induction of cripto-1 (one-eyed pinhead) inhibits zebrafish caudal fin regeneration

“…Additionally, a recent proteomic analysis of the Cripto-1 interactome identified 51 Cripto-1 binding proteins from human epithelial cells including regulators of extracellular exosomes, myosin II complexes, and the cytoskeleton. The myosin II activity was shown to regulate subcellular localization of Cripto-1 in epithelial and mesenchymal stem cell populations and to function cooperatively with zebrafish Cripto-1 to promote caudal fin regeneration [50]. Although we were unable to localize cripto-1 expression in the fin, these new data suggest that Cripto-1 may be expressed in both epithelial and mesenchymal cells following BDP exposure.…”

A Multidisciplinary Review of the Roles of Cripto in the Scientific Literature Through a Bibliometric Analysis of its Biological Roles

“…An unbiased screen for novel Cripto binding proteins using a non-transformed human mammary epithelial cell line (MCF10A) expressing a Flag-Cripto protein identified Myosin 9 (MYH9), a member of the Myosin II complex, as a Cripto interactor. The treatment of MCF10A Flag-Cripto cells with Myosin II inhibitor impaired Cripto localization to the cell membrane and its release in the culture media [82].…”