In an astrological chart the Sun represents identity, vitality, power, authority, ego and the true Self. The Sun as atmakaraka prompts us to develop Self-awareness and, ultimately, to become Self-Realized.
Atmakaraka translates as indicator of the soul. The atmakaraka reveals the unfulfilled desires that we carry with us and which have brought us into this incarnation. These deep desires need to be addressed and reveal our dharma, or soul purpose, in this life.