While the coronavirus’s spike protein has been the primary focus of researchers searching for COVID-19 treatments and vaccines, it may be the less-studied membrane glycoprotein that could be markedly aiding in the pathogen’s rapid proliferation, replication and immune evasion, according to a newly published study from the Lankenau Institute for Medical Research (LIMR).
Sunil Thomas, PhD, research assistant professor at LIMR, performed in silico analyses of SARS-CoV-2 and its four structural proteins: spike, envelope, nucleocapsid and membrane glycoprotein (M). He found that the M protein is homologous to the sugar transport protein SemiSWEET.
“Sugar transporters are essential for the maintenance of blood glucose levels in animals and in bacterial nutrition,” said Dr. Thomas. “Our finding may shed light on the clinical observation that COVID-19 patients with diabetes have a three-fold higher mortality rate than patients without diabetes, and that patients without diabetes may get the disorder after being infected. Diabetes may create a physiological environment that favors proliferation of this virus whose most abundant structural protein, the M protein, resembles a sugar transporter.”
The sugar transporters on the viral envelope, he added, may be aiding in rapid proliferation of the virus.
Dr. Thomas also noted that, to his knowledge, this is the first report of the presence of a sugar transporter-like structure in a virus membrane. It’s unknown if the M protein fuses to a healthy cell membrane, but if it does, the protein may aid in increased sugar uptake into cells, thereby influencing the cell’s energy metabolism. “The presence of a SemiSWEET glucose transporter in the virus’s M protein could be serving as an efficient mechanism to induce rapid viral proliferation and immune evasion,” said Dr. Thomas.
His peer-reviewed manuscript, “The structure of the membrane protein of SARS-CoV-2 resembles the sugar transporter SemiSWEET,” was published in the journal Pathogens and Immunity. This research was funded by the Women’s Board of Lankenau Medical Center.