Explainer: How the Wuhan virus infects human cells

WASHINGTON — Researchers from China have used cryo-electron microscopy to show how SARS-CoV-2 infects humans. The study published in Science says the virus targets a type of receptor found on human cells in the lungs, heart, kidneys and intestines.

Citing Kingston University microbiologist Mark Fielder, Sky News reports that the virus seems to attack two types of lung cells: goblet cells that coat the respiratory tract with mucus, and ciliated cells that usually filter out pathogens.

A previous study published in Science found the virus' spike protein has two receptor binding domains, or RBDs, facing downward and another facing upward. These allow the virus to bind with and invade human cells.

According to the new study, the virus targets a human ACE2 receptor that has bonded with an amino acid transporter. This subtype of ACE2 structure has never been discovered before.

The virus uses the spike protein's 'up' RBD to penetrate the cell. The virus then dissolves its own protein shell and releases its RNA payload inside the cell, according to the British Society for Immunology.

A study in Frontiers in Microbiology says a coronavirus hijacks the cell's structure to reproduce. The viral RNA takes over the host cell's endoplasmic reticulum to replicate itself and to manufacture the protein parts to make new viruses."

According to the Society for Immunology, the hijacked cell's Golgi bodies then package viral RNA and proteins in a viral protein shell. This leads to the creation of new viruses that leave the infected cell via the membrane.

The study in Frontiers in Microbiology says coronavirus takeover imposes stress on the host cell. Cell death, or apoptosis, is the result when the infection overwhelms the host cell's ability to maintain homeostasis.