Clathrin-dependent entry of severe acute respiratory syndrome coronavirus into target cells expressing ACE2 with the cytoplasmic tail deleted

J Virol. 2007 Aug;81(16):8722-9. doi: 10.1128/JVI.00253-07. Epub 2007 May 23.


The penetration of various viruses into host cells is accomplished by hijacking the host endocytosis machinery. In the case of severe acute respiratory syndrome coronavirus (SARS-CoV) infection, viral entry is reported to require a low pH in intracytoplasmic vesicles; however, little is known about how SARS-CoV invades such compartments. Here we demonstrate that SARS-CoV mainly utilizes the clathrin-mediated endocytosis pathway for its entry to target cells by using infectious SARS-CoV, as well as a SARS-CoV pseudovirus packaged in the SARS-CoV envelope. The SARS-CoV entered caveolin-1-negative HepG2 cells, and the entry was significantly inhibited by treatment with chlorpromazine, an inhibitor for clathrin-dependent endocytosis, and by small interfering RNA-mediated gene silencing for the clathrin heavy chain. Furthermore, the SARS-CoV entered COS7 cells transfected with the mutant of ACE2 with the cytoplasmic tail deleted, SARS-CoV receptor, as well as the wild-type ACE2, and their entries were significantly inhibited by treatment with chlorpromazine. In addition, ACE2 translocated into EEA1-positive early endosomes immediately after the virus attachment to ACE2. These results suggest that when SARS-CoV binds ACE2 it is internalized and penetrates early endosomes in a clathrin-dependent manner and that the cytoplasmic tail of ACE2 is not required for the penetration of SARS-CoV.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • COS Cells
  • Cell Line, Tumor
  • Chlorocebus aethiops
  • Chlorpromazine / pharmacology
  • Clathrin / antagonists & inhibitors
  • Clathrin / genetics
  • Clathrin / metabolism*
  • Cytoplasm / enzymology
  • Endocytosis* / drug effects
  • Endosomes / virology
  • Humans
  • Peptidyl-Dipeptidase A / genetics
  • Peptidyl-Dipeptidase A / metabolism*
  • RNA, Small Interfering / drug effects
  • SARS Virus / drug effects
  • SARS Virus / physiology*
  • Sequence Deletion
  • Virus Internalization* / drug effects


  • Clathrin
  • RNA, Small Interfering
  • Peptidyl-Dipeptidase A
  • angiotensin converting enzyme 2
  • Chlorpromazine