In auctex if one has a selected region and then apply the command `c-c c-e` (LaTeX-environment) then selecting an environment, then the selected region is folded between that environment.

Is there a similar command to put a selected region between an ordinary command (not begin-end environments, but ordinary latex environment). 

As a specific example assume that I would like to put the selected region between the braces in `\underline{}`. Is there a command which takes the name of the environment (in this case `unerline`) then put the selected region between the braces in `\underline{}`?