ABSTRACT
The recently discovered HAPSTR1 protein broadly oversees cellular stress responses. This function requires HUWE1, a ubiquitin ligase that paradoxically marks HAPSTR1 for degradation, but much about this pathway remains unclear. Here, leveraging multiplexed proteomics, we find that HAPSTR1 enables nuclear localization of HUWE1 with implications for nuclear protein quality control. We show that HAPSTR1 is tightly regulated and identify ubiquitin ligase TRIP12 and deubiquitinase USP7 as upstream regulators titrating HAPSTR1 stability. Finally, we generate conditional Hapstr1 knockout mice, finding that Hapstr1-null mice are perinatal lethal, adult mice depleted of Hapstr1 have reduced fitness, and primary cells explanted from Hapstr1-null animals falter in culture coincident with HUWE1 mislocalization and broadly remodeled signaling. Notably, although HAPSTR1 potently suppresses p53, we find that Hapstr1 is essential for life even in mice lacking p53. Altogether, we identify novel components and functional insights into the conserved HAPSTR1-HUWE1 pathway and demonstrate its requirement for mammalian life.
Subject(s)
Tumor Suppressor Protein p53 , Ubiquitin-Protein Ligases , Animals , Mice , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism , Ubiquitin-Protein Ligases/genetics , Ubiquitin-Protein Ligases/metabolism , Ubiquitin/metabolism , Ubiquitination/genetics , Nuclear Proteins/metabolism , Signal Transduction/genetics , Mammals/metabolismABSTRACT
The development of KRAS inhibitors was a remarkable feat, yet their efficacy is limited by inevitable resistance. In the September issue of Science, Lv et al.1 demonstrate how KRAS-driven cancers rewire signaling to restore protein homeostasis and acquire resistance to KRAS inhibitors with implications for novel combination therapeutic strategies.
Subject(s)
Neoplasms , Proteostasis , Humans , Proto-Oncogene Proteins p21(ras)/genetics , Protein Kinase Inhibitors/pharmacology , Protein Kinase Inhibitors/therapeutic use , Neoplasms/drug therapy , Signal Transduction , MutationABSTRACT
Patients with prostate cancer (PCA) are increasingly being offered germline genetic testing for precision therapy, precision management, and clinical trial options. Genetic test results also have implications for family members. How men with PCA perceive their genetic test results and decide whether to share recommendations with family members is not well studied. We interviewed 12 patients who had PCA and genetic testing and received a positive variant/likely positive variant (PV/LPV) (n = 7) or a variant of unknown significance (VUS) (n = 5) result. The semi-structured interview had five sections: genetic testing experience, impact, and interpretation of the test result, deciding whether to communicate test results to family members, impact of communication on family members, and suggestions for genetic counselors and other PCA patients. Interviews were transcribed verbatim and thematic analysis was completed using NVivo software v10. Receipt of PV/LPV or VUS genetic test results was not as emotional as receiving the diagnosis of PCA itself. Seven of the 12 participants chose to share their test results with all relevant family members, 4 chose to share with select family members, and one chose to not disclose to any family members. The majority of family members who were aware of participants' genetic results have not undergone cascade genetic testing or sought cancer screening. Participants with PCA and positive or VUS genetic test results typically share their results with at least immediate family members, but some communication barriers exist. Understanding the best way to provide actionable and relevant information about genetic testing to family members remains a challenge.
