Upon exposure to various environmental stresses such as arsenite, hypoxia, and 
heat shock, cells inhibit their translation and apoptosis and then repair 
stress-induced alterations, such as DNA damage and the accumulation of misfolded 
proteins. These types of stresses induce the formation of cytoplasmic RNA 
granules called stress granules (SGs). SGs are storage sites for the many mRNAs 
released from disassembled polysomes under these stress conditions and are 
essential for the selective translation of stress-inducible genes. 
Ras-GTPase-activating protein SH3 domain-binding protein 1 (G3BP1) is a 
component of SGs that initiates the assembly of SGs by forming a multimer. In 
this study, we examined the role of G3BP2, a close relative of G3BP1, in SG 
formation. Although single knockdown of either G3BP1 or G3BP2 in 293T cells 
partially reduced the number of SG-positive cells induced by arsenite, the 
knockdowns of both genes significantly reduced the number. G3BP2 formed a 
homo-multimer and a hetero-multimer with G3BP1. Moreover, like G3BP1, the 
overexpression of G3BP2 induced SGs even without stress stimuli. Collectively, 
these results suggest that both G3BP1 and G3BP2 play a role in the formation of 
SGs in various human cells and thereby recovery from these cellular stresses.