Table 1.

Actin-binding proteins: physiological role and involvement in AD.

Protein	Physiological Function	Role in AD
Arp2/3	Actin filaments nucleator: major actin-binding protein with polymerizing and filament branching activities	Required for Hirano body formation in Dictyostelium
Profilin	Responsible for the ADP to ATP nucleotide exchange on actin	Required for model Hirano body formation in Dictyostelium
Rho family of GTPases	Intermediaries between external signals and internal actin organization	- Increased activity of Rac1/Cdc42 Rho GTPases upon fibrillar Aβ exposure - Rac1 is increased in plasma samples of AD patients and abnormally activated in AD mice at early stages
ADF/cofilin	Promote the actin turnover	- Identified in the Hirano bodies and main component of actin rods -Alterations of its activation in in vitro and in vivo AD models
Myosins V and VI	Actin-based motor proteins	Myosin VI colocalizes with tau protein accumulated in neurons of AD patients
Drebrin	Bundles actin filaments by crosslinking	Decreased in the hippocampal dendritic spines of AD patients and in the hippocampus of AD mice
α-actinin	Form dimers that crosslink actin filaments	Component of the Hirano bodies
Tropomyosins	Form head-to-tail polymers to stabilize the actin filament and recruit myosin	Component of neurofibrillary pathology and Hirano bodies