Does A primarchs mother hold any political power?

I'm curious if a primarchs mother (Tarasha) holds political and military influence. I read somewhere where she talked back to a Ultramarine Captain who said "With all due respect my lady" to tarasha. So she absolutely holds some type of position and I'm curious as to what. I'm Guessing more of a...Symbolic position. Like she can't Command ultramarines or Astra militarum Squads but nobody would dare disrespect girly man's mother but that's my assumption.