Integrins are transmembrane heterodimeric glycoproteins responsible for cellular communication; therefore, they play an essential role in many physiological events.
Transforming growth factor β (TGF- β) family proteins participate in a variety of biological events and diseases, including cell proliferation, immune response, apoptosis, oncogenesis and many physiological events.
PGE2, a major prostaglandin produced via arachidonic acid (AA) metabolism, is involved in many physiological events, such as cell growth, immune regulation, inflammation and arthritis [ 3].
Since RA plays crucial roles in many physiological events, such as embryonic development, reproduction, metabolism and homeostasis [ 15], RAIGs are considered essential to RA-dependent physiological events.
Protein glycosylation is the most common and complex posttranslational modification involved in many physiological events, including protein folding and trafficking, cell-cell and cell-matrix interactions, cellular differentiations and the immune response [ 1– 5].
Cyclic AMP is a diffusible intracellular second messenger, which influences many physiological events, by transducing hormone and small molecule effects into activation of protein kinases, modulating calcium transport and regulating gene activation.
Many basic physiological events, such as relaxed breathing and certain nervous system functions do, too.
Protein tyrosine phosphorylation plays essential roles in many cellular physiological events, such as cell growth, division, differentiation, adhesion, motility, and death [1].
The ROS produced by this enzyme regulate many fundamental physiological events in the cell (Brown and Griendling 2009), but excessive ROS production causes cellular dysfunctions, such as an increase in stretch-induced Ca2+ influx into mdx myofibres resulting in force reduction (Whitehead et al. 2010).
Reactive nitrogen species (RNS), such as nitric oxide and its higher oxides, play important roles in cell signaling during many physiological and pathological events.
Thus many physiological and pathological events are closely related to persistent protease activity.
