I have Already described permanent significations of the Grahas in Indian Vedic Astrology System. Apart from those, the Grahas also have a set of significations that changes according to the degree within the sign. The degree within the sign is always a number between 0-30, and the closer a Graha is towards the end of the sign, the more important it’s signification is
Because Rahu moves backwards through the zodiac, its position is measured from the end of the sign for this purpose. In other words, you subtract the degree from 30 and use the result.

Whichever Graha is in the highest degree, is called the Atma karaka. “Atmameans self or soul, and “karakameans significator in Sankrit. Therefore, the Graha that becomes atmakaraka is a significator for the self. Whatever influences on the atmakaraka are found in the chart, will have a significant influence on the person’s deepest nature.
The Graha that is in the next highest degree is called the Amatya karaka. The Amatya karaka signifies Ministership. There is almost no information available from the classics, so the use of these karakas has to be obtained from their names, and the few places where references are made.
The Graha that is the 3rd highest degree is called Bhratru Karaka(Brother/Sister), the 4th is Matru Karaka(Mother), the 5th is Pitru karaka(Father), the 6th is Putra karaka(Son/Daughter), the 7th is Gnati karaka(Knowledge/Wisdom), the 8th is Stree karaka(Spouse).
Parashara indicates two systems in this regard: one system considers 8 karakas, and another considers 7 karakas. In case only 7 karakas are considered, the Matrukaraka and Putrakaraka are the same

According to Sage Parashara : “Just as a minister cannot go against the king, the other karakas cannot predominate over the Atmakaraka in the affairs of the native. If the atmakaraka is afflicted, the other karakas cannot give their positive results properly. But if the Atmakaraka is favorable, afflictions on the other karakas cannot prevail”

Basic Elements of Vedic Astrology
Astronomical basis of Vedic Astrology