Table 1.

In vivo giActin function versus known components

Function	Giardia	Other eukaryotes
Actin nucleation (24)	?*	Arp2/3, formin, spire, Cobl, leiomodin
Actin signaling (50)	giRac	Rho, Rac, Cdc42
Downstream of G protein (50)	PAK, ?	PAK, cofilin, myosin, formin, Arp2/3, gelsolin
Endocytosis (44)	Clathrin, dynamin, ?	Clathrin, dynamin, Wasp, Wasp regulators, Arp2/3, Arp2/3 activators, myosin, fimbrin, Abp1, capping proteins
Cytokinesis (contractile) (51)	None	Rho, myosin, formin, annilin, cofilin, capping protein
Cytokinesis (vesicular delivery, midbody phragmoplast) (34)	Dynamin, Sec1, Snap, CDC48, Rab11	Dynamin, Sec1, Snap25, CDC48p, Rab11
Flagella (inner arm dynein) (17)	giActin, p28, centrin	Actin, p28, centrin

GiActin forms stage-specific structures and performs core cellular processes. Conserved components found in Giardia and other eukaryotes are listed.

*The placement of distinct organized giActin structures suggests the presence of a protein or protein complex that controls giActin nucleation.