Role of the V2R-ßarrestin-Gßγ complex in promoting G protein translocation to endosomes.

Classically, G protein-coupled receptors (GPCRs) promote signaling at the plasma membrane through activation of heterotrimeric Gαßγ proteins, followed by the recruitment of GPCR kinases and ßarrestin (ßarr) to initiate receptor desensitization and internalization. However, studies demonstrated that some GPCRs continue to signal from internalized compartments, with distinct cellular responses. Both ßarr and Gßγ contribute to such non-canonical endosomal G protein signaling, but their specific roles and contributions remain poorly understood. Here, we demonstrate that the vasopressin V2 receptor (V2R)-ßarr complex scaffolds Gßγ at the plasma membrane through a direct interaction with ßarr, enabling its transport to endosomes. Gßγ subsequently potentiates Gαs endosomal translocation, presumably to regenerate an endosomal pool of heterotrimeric Gs. This work shines light on the mechanism underlying G protein subunits translocation from the plasma membrane to the endosomes and provides a basis for understanding the role of ßarr in mediating sustained G protein signaling.

Racial and ethnic disparities in genomic testing among lung cancer patients: a systematic review.

BACKGROUND: Racial and ethnic disparities in genomic testing could exacerbate disparities in access to precision cancer therapies and survival-particularly in the context of lung cancer where genomic testing has been recommended for the past decade. However, prior studies assessing disparities in genomic testing have yielded mixed results. METHODS: We conducted a systemic review to examine racial and ethnic disparities in the use of genomic testing among lung cancer patients in the United States. Two comprehensive searches in PubMed, Embase, and Scopus were conducted (September 2022, May 2023). Original studies that assessed rates of genomic testing by race or ethnicity were included. Findings were narratively synthesized by outcome. RESULTS: The search yielded 2739 unique records, resulting in 18 included studies. All but 1 study were limited to patients diagnosed with non-small cell lung cancer. Diagnosis years ranged from 2007 to 2022. Of the 18 studies, 11 found statistically significant differences in the likelihood of genomic testing by race or ethnicity; in 7 of these studies, testing was lower among Black patients compared with White or Asian patients. However, many studies lacked adjustment for key covariates and included patients with unclear eligibility for testing. CONCLUSIONS: A majority of studies, though not all, observed racial and ethnic disparities in the use of genomic testing among patients with lung cancer. Heterogeneity of study results throughout a period of changing clinical guidelines suggests that minoritized populations-Black patients in particular-have faced additional barriers to genomic testing, even if not universally observed at all institutions.