You can go to System Pref -> International -> Input Menu and
1. tick "Show input menu ..."
2. Character palette
3. Tick also US layout (or better tick English International that has the same number of keys - US has one less).
afterward, from the menu bar you can
- switch to US layout and type as if you were on a US keyboard
- open the character palette and look for the symbol
On the italian keyboard, { } and other symbols are missing. You can obtain those braces (on IT layout and on others without curly braces) by pressing
opt+shift+[ ]
thistle