actin biology

how TB-500 sequesters G-actin monomers and controls cytoskeletal dynamics during tissue repair

the actin connection

TB-500's defining function is G-actin sequestration. every nucleated cell keeps a pool of unpolymerized actin; TB4 holds those monomers until the cell needs to move, divide, or rebuild.

that buffered pool powers TB-500's effects on wound healing. without TB4, G-actin would polymerize on its own and the cell would lose the on-demand scaffolding it needs to migrate.

every mechanism on this page is from in-vitro or animal work. no human injectable TB4 trial has measured actin-pool dynamics directly.

actin biology at a glance

four numbers that frame the TB4 -- actin system.

43 aa

TB4 length -- almost all actin-binding surface

LKKTET

motif that docks into G-actin's subdomain 1-2 cleft

1:1

TB4 -- G-actin binding stoichiometry

~0.7 uM

TB4 -- actin dissociation constant

see G-actin to F-actin in motion

adjust TB-500 levels and watch the equilibrium shift.

actin dynamics simulator

TB4

sequesters G-actin, blocking polymerization until needed

profilin

delivers monomers to barbed-end elongation sites

~1:3

profilin-to-TB4 ratio that sets the polymerization set-point

Knowledge Check

Test what you've learned in this unit.

Practice Exercises

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