Table 1.
Cleavability of NiV and MV F proteins by cathepsin L, furin and trypsin.
| Cleavage site sequence | Cleavage by |
|||
|---|---|---|---|---|
| Cathepsin L | Furin | Trypsin | ||
| NiVF | G-D-V-R | +++ | – | −/+a |
| NiVFcm1 | N-H-N-R | ++ | – | – |
| NiVFcm2 | R-H-K-R | – | – | –b |
| NiVFg3 | G-D-V-R | +++ | – | −/+a |
| NiVFg3cm2 | R-H-K-R | +/− | – | –b |
| MVFEdm | R-H-K-R | – | +++ | ++b |
| MVFcm | N-H-N-R | – | – | ++ |
| MV Fcm* | G-D-V-R | – | – | + |
Boldfaced letters indicate basic amino acids at the cleavage site.
The results on the cleavability of standard and mutant F proteins are summarized: +++ very efficient cleavage; ++ efficient cleavage; + cleavage clearly detectable; +/− cleavage barely detectable; – no cleavage.
a
Analysis of the endocytosis-negative mutants NiV FYA (Fig. 3A) and NiV Fg3YA (suppl. Fig. II) had revealed that the NiV F cleavage site is slightly processed if constitutively expressed on the cell surface.
b
Data not shown in this study.