 When TPC2 expression is decreased or knocked out, there is a resultant elevation in production of melanin and thus melanosomal pH, and when TPC2 expression is increased, there is less production of melanin.TPCs also are involved in nutrient detection as they become active constitutively on identifying the status of the nutrients.This is done by direct communication between the TPCs and mammalian/mechanistic targets of rapamycin (mTORs), which are associated with detecting levels of oxygen, nutrients, and energy in the cells and thus help with regulation of metabolism.