Explicitly Lock A Table?

I have multiple applications which can potentially update the same trigger simultaneously. Each application:

(1) Reads the contents of the current trigger
(2) Creates a new trigger based on the current contents
(3) Drops the trigger
(4) Creates the new trigger

I need to insure that once one application begins step (1), then no other application can start step (1) until step (4) has completed.

Any ideas on how this can be done? Some databases have a concept of locking tables explicitly, so for them, I can do:

(0) lock table foo;
(1) - (4)
(5) unlock table foo;

Is there such a concept in mysql or is there another way of accomplishing this?

Thanks,
Eric