Are you familiar with foreign keys? If not, do a little R&D on the topic.
The status_update table has an ID field of its own (say, updateID) and references the profileID of the user making the update.
Your replies table will reference the profileID of the user making the reply, and also the primary key field from the status_update table.
So, to display a user's page along with their updates and all replies, your SQL may look something like this (all column names are made-up, but you should get the idea):
replies r on s.upateID = r.updateID
users u on r.profileID = u.profileID
u.profileID = @some_users_id
The left joins are used to ensure with no replies are not filtered out.