4E-BP1 Is a Tumor Suppressor Protein Reactivated by mTOR Inhibition in Head and Neck Cancer.

Aberrant activation of the PI3K-mTOR signaling pathway occurs in >80% of head and neck squamous cell carcinomas (HNSCC), and overreliance on this signaling circuit may in turn represent a cancer-specific vulnerability that can be exploited therapeutically. mTOR inhibitors (mTORi) promote tumor regression in genetically defined and chemically induced HNSCC animal models, and encouraging results have been recently reported. However, the mTOR-regulated targets contributing to the clinical response have not yet been identified.

GNAS Induces Pancreatic Cystic Neoplasms in Mice That Express Activated KRAS by Inhibiting YAP1 Signaling.

Background & Aims: Mutations at hotspots in GNAS, which encodes stimulatory G-protein, α subunits, are detected in approximately 60% of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas. We generated mice with KRAS-induced IPMNs that also express a constitutively active form of GNAS in pancreas and studied tumor development.

Methods: We generated p48-Cre; LSL-KrasG12D; Rosa26R-LSL-rtTA-TetO-GnasR201C mice (Kras;Gnas mice); pancreatic tissues of these mice express activated KRAS and also express a mutant form of GNAS (GNAS) upon doxycycline administration.

Expression of an active Gα mutant in skeletal stem cells is sufficient and necessary for fibrous dysplasia initiation and maintenance.

Fibrous dysplasia (FD) is a disease caused by postzygotic activating mutations of (R201C and R201H) that encode the α-subunit of the G stimulatory protein. FD is characterized by the development of areas of abnormal fibroosseous tissue in the bones, resulting in skeletal deformities, fractures, and pain. Despite the well-defined genetic alterations underlying FD, whether activation is sufficient for FD initiation and the molecular and cellular consequences of mutations remains largely unresolved, and there are no currently available targeted therapeutic options for FD.

Genetic evidence that β-arrestins are dispensable for the initiation of β-adrenergic receptor signaling to ERK.

The β-adrenergic receptor (βAR) has provided a paradigm to elucidate how G protein-coupled receptors (GPCRs) control intracellular signaling, including the discovery that β-arrestins, which bind to ligand-activated GPCRs, are central for GPCR function. We used genome editing, conditional gene deletion, and small interfering RNAs (siRNAs) to determine the roles of β-arrestin 1 (β-arr1) and β-arr2 in βAR internalization, trafficking, and signaling to ERK. We found that only β-arr2 was essential for βAR internalization.