Meaning of 就いて in Japanese

It seems that 就いて(tsuite) is an inflection of 就く with the following forms:

Definition of 就いて

ついて(tsuite) 【就いて】

(exp) about; concerning; as to; regarding
そのことついては私に責任があります。
I'm to be blamed for that matter.

について(nitsuite) 【に就いて ·に就て ·に付いて】

ついては(tsuiteha) 【就いては】

(conj) in line with this; therefore; consequently; so; such being the case; in that regard; in this connection
ついては、私の手紙のコピーを添付いたします。
I am sending a copy of my letter to you.

彼女かのじょは有望な仕事しごとに就いている。

She has a job with good prospects.

彼かれはどんな職業しょくぎょうに就いていますか。

What line is he in?

The doctors thought he was dead, but today he is still alive and healthy, and has a job and a family.

どんな職業しょくぎょうに就いていますか。

What line are you in?