Expansin

Expansin is a plant-cell enzyme that is involved in cell expansion. It is involved in

Because the cell wall is quite high in tensile strength, it must be weakened prior to the extension of the microfibrils of cellulose, strands of hemicellulose, and (in some cases) lignin

Families
Thus far, 2 general families of expansins have been discovered, the alpha-expansins and the beta-expansins.

Actions
Expansins help to reduce wall stress as well as wall creep, which over time would cause a loss of structural integrity in the cell.

Mechanism
While most details of how expansins play a role in cell elongation are still not completely worked out; there is evidence that the action of expansin's is to interrupt (break) the hydrogen-bonds between the cell wall and their pectin (gel) matrix, the cells are allowed to expand by increasing polymerization (lengthen the polymer of cellulose fibrils) thereby increasing the length of the cell wall and therefore, the cell itself