CHC22 clathrin recruitment to the early secretory pathway requires two-site interaction with SNX5 and p115.

The two clathrin isoforms, CHC17 and CHC22, mediate separate intracellular transport routes. CHC17 performs endocytosis and housekeeping membrane traffic in all cells. CHC22, expressed most highly in skeletal muscle, shuttles the glucose transporter GLUT4 from the ERGIC (endoplasmic-reticulum-to-Golgi intermediate compartment) directly to an intracellular GLUT4 storage compartment (GSC), from where GLUT4 can be mobilized to the plasma membrane by insulin. Here, molecular determinants distinguishing CHC22 from CHC17 trafficking are defined. We show that the C-terminal trimerization domain of CHC22 interacts with SNX5, which also binds the ERGIC tether p115. SNX5, and the functionally redundant SNX6, are required for CHC22 localization independently of their participation in the endosomal ESCPE-1 complex. In tandem, an isoform-specific patch in the CHC22 N-terminal domain separately mediates binding to p115. This dual mode of clathrin recruitment, involving interactions at both N- and C-termini of the heavy chain, is required for CHC22 targeting to ERGIC membranes to mediate the Golgi-bypass route for GLUT4 trafficking. Interference with either interaction inhibits GLUT4 targeting to the GSC, defining a bipartite mechanism regulating a key pathway in human glucose metabolism.

Evidence of SARS-CoV-2 Antibody in Mississippi White-Tailed Deer.

Background: Early detection and monitoring of SARS-CoV-2 infections in animal populations living in close proximity to humans is crucial for preventing reverse zoonosis of new viral strains. Evidence accumulated has revealed widespread SARS-CoV-2 infection among white-tailed deer (WTD), (Odocoileus virginianus) populations in the United States except in the southeast region. Therefore, the objective was to conduct surveillance for evidence of SARS-CoV-2 infection among WTD in Mississippi. Materials and Methods: Blood, kidney tissues, and nasal swab samples were collected in 17 counties from hunter-harvested deer during 2021-2022 and 2022-2023.Samples of kidney tissue were collected to evaluate for detecting antibody as a possible alternative to blood that is not always available from dead WTD. Nasal swab samples were tested for SARS-CoV-2 viral RNA by a RT-PCR assay. Sera and kidney tissue samples were tested for SARS-CoV-2 antibody by an enzyme-linked immunoassay (ELISA) and sera by a plaque reduction neutralization test (PRNT80). Results: The results of testing sera and kidney homogenate samples provided the first evidence of SARS-CoV-2 infection among WTD in Mississippi. The infection rate during 2021-2022 was 67% (10/15) based on the detection of neutralizing antibody by the PRNT80 and 26%(16/62) based on the testing of kidney tissue homogenates by an ELISA, and viral RNA was detected in 25% (3/12) of nasal swab samples. In 2022 to 2023, neutralizing antibody was detected in 62% (28/45) of WTD serum samples. In contrast, antibodies were not detected in 220 kidney homogenates by an ELISA nor was viral RNA detected in 220 nasal swab samples. Evidence of WTD activity was common in urban areas during the survey. Conclusion: Overall, the findings documented the first SARS-CoV-2 infection among WTD in Mississippi and showed that WTD commonly inhabited urban areas as a possible source of acquiring infection from humans infected with this virus.