▁is ▁no ▁competition ▁between ▁alpha - c aten in ▁and ▁E - c ad her in ▁or ▁between ▁T CF 1 ▁and ▁B CL 9 , ▁respectively . ▁On ▁the ▁other ▁hand , ▁B CL 9 ▁and ▁B CL 9 L ▁must ▁comp ete ▁with ▁α - c aten in ▁to ▁access ▁ β - c aten in ▁mole cules . ▁ ▁Function ▁ ▁Reg ulation ▁of ▁de grad ation ▁through ▁ph osph ory lation ▁▁ ▁The ▁cell ular ▁level ▁of ▁beta - c aten in ▁is ▁mostly ▁controlled ▁by ▁its ▁u bi quit ination ▁and ▁prote os om al ▁de grad ation . ▁The ▁E 3 ▁u bi quit in ▁lig ase ▁Tr CP 1 ▁( also ▁known ▁as ▁ β - Tr CP ) ▁can ▁recognize ▁ β - c aten in ▁as ▁its ▁substr ate ▁through ▁a ▁short ▁linear ▁mot if ▁on ▁the ▁dis ordered ▁N - ter minus . ▁However , ▁this ▁mot if ▁( A sp - Ser - G ly - I le - H is - Ser ) ▁of ▁ β - c aten in ▁needs ▁to ▁be ▁ph osph ory l ated ▁on ▁the ▁two ▁ser ines ▁in ▁order ▁to ▁be ▁capable ▁to ▁bind ▁ β - Tr CP . ▁Ph osph ory lation ▁of ▁the ▁mot if ▁is ▁performed ▁by ▁G ly c ogen ▁Syn th ase ▁Kin ase ▁ 3 ▁alpha ▁and ▁beta ▁( GS K 3 α ▁and ▁G SK 3 β ). ▁G SK 3 s ▁are ▁const itut ively ▁active