Modulation of protein intrinsic activity in cells is generally carried out via a combination of
four common ways, i.e., allosteric regulation, covalent modification, proteolytic cleavage and association
of other regulatory proteins. Accumulated evidence indicate that changes of certain abiotic factors
(e.g., temperature, pH, light and mechanical force) within or outside the cells directly influence protein
structure and thus profoundly modulate the functions of a wide range of proteins, termed as abiotic
regulatory proteins (e.g., heat shock factor, small heat shock protein, hemoglobin, zymogen, integrin,
rhodopsin). Such abiotic regulation apparently differs from the four classic ways in perceiving and response to the signals.
Importantly, it enables cells to directly and also immediately response to extracellular stimuli, thus facilitating the ability
of organisms to resist against and adapt to the abiotic stress and thereby playing crucial roles in life evolution. Altogether,
abiotic regulation may be considered as a common way for proteins to modulate their functions.