If you can, it is preferable that you use a different email address to that supplied by your employers.

First, it may be a breach of your employment contract to use such an address, which may lead to other consequences.

Secondly, many employers add a disclaimer and confidentiality notice to the bottom of all outgoing emails. This can be several lines long, and is often more. No one on the mailing list wants to see this, especially when it is often the case that it is longer than the actual message.