As of RTC 6.0.5, there is no one-click action that will lock a component in all streams where it is used. I do not believe there is an existing enhancement or RFE already capturing this request either. I suspect such an enhancement might fall lower on the priority list as well as we tend to avoid single actions that may impact multiple Project/Team Areas at once - since in this case, streams that contain the same component may be owned by different Project/Team Areas (and it's a rare use case to have one individual dictate that a component should be locked in all Project/Team Areas)
You may have to settle on manually locking streams (or components in a stream) individually, or to setup preconditions/advisors to help 'lock' down streams/components as needed. You could also write your own 'code' to lock down a set of streams/components in batch, either using the plain-Java API, or writing a custom script which uses the SCM CLI (command line client).



As a reference for any readers of this post, here is a summary of some of the the lock options available:

In RTC 6.0.2 we added a feature that lets you lock streams and components to prevent deliveries to the files in those streams or components. Stream and component locks work in a similar manner to file locks but apply to the entire stream or the entire component in a stream. When a stream or component is locked, any attempted deliveries by users who do not own the lock will fail with an appropriate error message. The user that holds the lock can still perform deliveries to the stream. A lock does not only prevent deliveries, it also prevents any operation that affects the files in the locked component or stream. For example, a component replace is also prevented.

See:
-New & Noteworthy Mention: https://jazz.net/downloads/rational-team-concert/releases/6.0.2?p=newsDetails#stream-locking
-Stream/Component Locking Demo Video: https://www.youtube.com/watch?v=b8QwzwUF2ZY
-SCM Command Line Client 'set lock' command: https://www.ibm.com/support/knowledgecenter/SSCP65_6.0.4/com.ibm.team.scm.doc/topics/set_lock.html

Prior to 6.0.2, you could add a deliver advisor in the process spec to restrict deliveries to particular streams. By protecting your stream by particular roles or users, you can effectively lock the stream down.
"http://jazz.net/library/article/215#protect_some" describes how to protect individual components in a stream, the same approach can be used to lock down the entire stream..