Table 1.

Actin regulatory proteins in insulin-stimulated glucose transporter-4 (GLUT4) translocation.

Name	Function(s)	Binding partners?	Mode of activation	Role in GLUT4 translocation	Reference
Actin depolymerizing factor (cofilin)	Actin-severing protein, membrane protrusion, and cell motility	Chronophin, slingshot (SSH), LIMK	Activated by dephosphorylation of S3 by chronophin and SSH	Required in skeletal muscle cells	(111, 128, 129)
Alpha-actinin-4	Actin filament cross-linking protein, binds actin to the cortical cytoskeleton, and its associated proteins	GLUT4, MICAL-L2, Rab13, p85 subunit of PI3K, AKT1	Relieved of autoinhibition upon phospholipid binding	Required in skeletal muscle cells	(130–132)
Arp2/3 complex	Actin nucleation and branching	PAK1, WASP family proteins, cortactin	Activation by phosphorylation of its regulatory subunit ARPC1/p41-ARC at T21 by PAK1	Required in skeletal muscle cells	(127, 133)
Cortactin	Binds F-actin to prompt nucleation of new filaments	Arp2/3 complex, PAK, ERK, Src, WASP, dynamin	Phosphorylation at Y421, Y466, Y482, S405, and S418	Required in skeletal muscle cells	(134)
Gelsolin	Actin capping and severing protein	Nm23h1, STX4	Calcium binding to gelsolin leads to its activation	ND	(54, 135)
N-WASP	Strong nucleation promoting factor that binds to Arp2/3 complex to nucleate branched actin filaments	Cdc42, Src family kinases, WASP interacting SH3 protein, GRB2, cortactin	Relieved of autoinhibition by interaction with binding partner	Required in 3T3-L1 adipocytes and skeletal muscle cells	(127, 136)
WAVE-2	Regulates de novo actin polymerization	PIR121/Sra-1, Nap1, Abi1/2, HSCP300	Upon release from Rac1 and NCK, WAVE becomes activated	ND	(137, 138)
Tropomodulin 3	Actin-capping protein, negative regulator of cell migration	AKT2	Phosphorylation at S71	Required in 3T3-L1 adipocytes	(139)

ND, not determined.