TWF1 encodes twinfilin, an actin monomer-binding protein conserved from yeast to mammals. Studies of the mouse counterpart suggest that this protein may be an actin monomer-binding protein, and its localization to cortical G-actin-rich structures may be regulated by the small GTPase RAC1.
The deduced 350-amino acid protein has a calculated molecular mass of 40.3 kD. TWF1 has an N-myristoylation site and several sites for threonine, serine, and tyrosine phosphorylation, but it lacks a conserved protein kinase catalytic domain. Northern blot analysis detected a 3.4-kb transcript that was highly expressed in colon, testis, uterus, ovary, prostate, and lung. Lower expression was detected in brain, bladder, and heart, and no expression was detected in liver.