Video showing the internalization of VLP-Wuhan:(E, S, N, M&M-pHluorin) into A549. pHluorin emits bright fluorescent light in pH≥8 but its intensity sharply decreases at pH<7.5, completely disappearing at pH<5.As the M protein C-terminal domain lies inside the VLPs, the fused pHluorin serves as a real-time indicator of the intra-VLP pH. When added to the medium (pH8), pHluorin-labelled VLPs emitted a bright green signal. However, shortly after binding to the membrane of the cells, the intensity rapidly decreased.

A549

A549 cells are lung carcinoma epithelial cells.

mCherry cell labelling,

Freely diffusable mCherry.

SARS-CoV-2 VLPs Wuhan

Wild Type SARS-CoV-2 virus-like particles containing all the structural proteins.

M-pHluorin,

The Membrane protein of the VLP is labelled via pHluorin.

No treatment