Biochemical controls: two forms of actin (Introduction)

by David Turell , Monday, January 01, 2024, 18:36 (117 days ago) @ David Turell

Each has a separate role:

https://www.sciencedaily.com/releases/2023/12/231222145416.htm

"Researchers at the Universities of Göttingen and Warwick investigated the structure and mechanics of the main component of the cytoskeleton of the cell: a protein known as actin. Actin is found in all living cells where it has a range of important functions -- from muscle contraction to cell signalling and cell shape.

"This protein comes in two different varieties termed "isoforms," which are known as gamma actin and beta actin.

"The difference between the two proteins is miniscule, only a few amino acids at just one part of the molecule vary.

"Yet this small change has a big impact on the cell. In nature, normally only mixtures of the two isoforms are found.

***

"The results indicate that gamma actin prefers to form rigid networks near the cell's apex, while beta actin preferentially forms parallel bundles with a distinct organizational pattern. This difference is likely to be due to the stronger interaction of gamma actin with specific types of positively charged ions, rendering its networks stiffer than those formed by beta actin...The research advances scientists' understanding of fundamental cellular processes by shedding light on specific biological functions of actin, and this will have particular relevance for processes involving cellular mechanics such as growth, division and maturation of cells in tissue."

Comment: a tiny change in the molecule creates a major difference in the action it produces. We are left with the black box of understanding how the molecules exert their effect. It also raises the question of how this difference evolved to form the first cells. Design is required.