PCA1 (Protease Activator 1) is a key protein in specific signaling pathways, responsible for activating certain proteases, thus affecting processes such as cell growth, differentiation, and apoptosis. It is expressed in various cell types and tissues, playing a crucial role in certain signal transduction processes. PCA1's structure includes specific regions for recognizing and activating particular proteases. Its expression pattern is regulated by various factors, and gene mutations can lead to abnormal activation functions, affecting cell behavior and being associated with the development of certain diseases.