What are the alternative ways to say "paying attention"?

What could be a better way to express "reacting to something with immediate attention"? Like, assuming that you are a job seeker and you've overheard someone talking about a job opportunity, so at that moment, you suddenly become attentive and feel compelled to learn it among the other things you might have heard. I need a word for such a reaction.

By the way, it's not necessarily a dangerous or bad thing for you in this case. Just something that you feel important.

Solution 1:

An idiom that can be used in this situation is prick up (one's) ears

To become more or particularly alert, intrigued, or enthusiastic.

In your example, you could say

I'm looking for a job, so when I overheard someone talking about a job opportunity, my ears pricked up.

A variation of this spelling is perk up (one's) ears which is the one I'm more familiar with.