One of the functions of calcium binding proteins is to regulate the amount of free (unbound) Ca2+ in the cytosol of the cell.
Intracellular storage and release of Ca2+ from the sarcoplasmic reticulum is associated with the high-capacity, low-affinity calcium-binding protein calsequestrin.
This type of protein is also found in large quantities in malignant mesothelial cells, which can be easily differentiated from carcinomas.
P53 is known as a tumor suppressor protein and in this case acts as a transcriptional activator or repressor of numerous genes.
In mammals, P/Q-rich SCPP is also found in saliva and milk and includes unorthodox members such as MUC7 (a mucin) and casein.
[6] With their role in signal transduction, calcium-binding proteins contribute to all aspects of the cell's functioning, from homeostasis to learning and memory.