Final answer:
STN1 is not a member of the Shelterin Complex; it is a part of the CST complex, which also functions in telomere maintenance but is separate from Shelterin.
Step-by-step explanation:
The protein that is NOT a member of the Shelterin Complex among the options provided is STN1. The Shelterin Complex is composed of several proteins, including TRF1, TRF2, POT1, RAP1, TIN2, and TPP1. These proteins work together to protect chromosome ends, or telomeres, from being erroneously repaired as DNA damage. STN1 is part of the CST complex, which also plays a role in telomere maintenance but is not considered part of the Shelterin Complex.