Final answer:
The shelterin complex contains RAP1 which recruits POT1 and STN1 to bind to histone 3 and histone 4 N-terminal tails to trigger heterochromatin formation.
Step-by-step explanation:
The shelterin complex contains RAP1 which recruits POT1 and STN1. These two proteins bind to histone 3 and histone 4 N-terminal tails and trigger the formation of heterochromatin.