Transmembrane 9 Superfamily, Member 2 (TM9SF2)

TM9SF2 contains a putative signal sequence, a hydrophilic N-terminal region, and 9 predicted C-terminal transmembrane domains. TM9SF2 shares 35% amino acid sequence identity with the S. cerevisiae Emp70 protein. By indirect immunofluorescence microscopy, recombinant TM9SF2 appeared to be localized to endosomes by virtue of its apparent colocalization with transferrin receptors  and some mannose 6-phosphate receptors; TM9SF2 was not detected in the plasma membrane or in the Golgi apparatus. Northern blot analysis detected an approximately 3.2-kb TM9SF2 transcript in all human tissues tested, with the highest expression in pancreas, high expression in kidney, lower expression in heart, brain, skeletal muscle, and placenta, and the lowest expression in lung and liver.