Fused in sarcoma/translocated in liposarcoma (FUS/TLS) is one of causative genes 
for familial amyotrophic lateral sclerosis (ALS). In order to identify binding 
partners for FUS/TLS, we performed a yeast two-hybrid screening and found that 
protein arginine methyltransferase 1 (PRMT1) is one of binding partners 
primarily in the nucleus. In vitro and in vivo methylation assays showed that 
FUS/TLS could be methylated by PRMT1. The modulation of arginine methylation 
levels by a general methyltransferase inhibitor or conditional over-expression 
of PRMT1 altered slightly the nucleus-cytoplasmic ratio of FUS/TLS in cell 
fractionation assays. Although co-localized primarily in the nucleus in normal 
condition, FUS/TLS and PRMT1 were partially recruited to the cytoplasmic 
granules under oxidative stress, which were merged with stress granules (SGs) 
markers in SH-SY5Y cell. C-terminal truncated form of FUS/TLS (FUS-dC), which 
lacks C-terminal nuclear localization signal (NLS), formed cytoplasmic 
inclusions like ALS-linked FUS mutants and was partially co-localized with 
PRMT1. Furthermore, conditional over-expression of PRMT1 reduced the 
FUS-dC-mediated SGs formation and the detergent-insoluble aggregates in HEK293 
cells. These findings indicate that PRMT1-mediated arginine methylation could be 
implicated in the nucleus-cytoplasmic shuttling of FUS/TLS and in the SGs 
formation and the detergent-insoluble inclusions of ALS-linked FUS/TLS mutants.