Photochemical Identification of Auxiliary Severe Acute Respiratory Syndrome Coronavirus 2 Host Entry Factors Using μMap

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2),
the
infectious agent of the COVID-19 pandemic, remains a global medical
problem. Angiotensin-converting enzyme 2 (ACE2) was
identified as the primary viral entry receptor, and transmembrane
serine protease 2 primes the spike protein for membrane fusion. However, ACE2 expression is generally low and variable across tissues,
suggesting that auxiliary receptors facilitate viral entry. Identifying
these factors is critical for understanding SARS-Cov-2 pathophysiology
and developing new countermeasures. However, profiling host–virus
interactomes involves extensive genetic screening or complex computational
predictions. Here, we leverage the photocatalytic proximity labeling
platform μMap to rapidly profile the spike interactome in human
cells and identify eight novel candidate receptors. We systemically
validate their functionality in SARS-CoV-2 pseudoviral uptake assays
with both Wuhan and Delta spike variants and show that dual expression
of ACE2 with either neuropilin-2, ephrin receptor
A7, solute carrier family 6 member 15, or myelin and lymphocyte protein
2 significantly enhances viral uptake. Collectively, our data show
that SARS-CoV-2 synergistically engages several host factors for cell
entry and establishes μMap as a powerful tool for rapidly interrogating
host–virus interactomes.