SARS‐CoV2 (Severe acute respiratory syndrome coronavirus 2), the causative pathogen of COVID‐19, is known to bind to the ACE2 receptor (Angiotensin‐converting enzyme 2) via RBD (receptor binding domain) of virus’ Spike protein, which triggers ACE2‐mediated endocytosis for subsequent infection processes (Figure 7a).[39] In this experiment, the fluorescently labeled Spike protein derived from SARS‐CoV2 was incubated with HeLa cells stably expressing human ACE2. Here, ACE2 is linked to COVID-19.