Figure 2.

Localization to the plasma membrane, uptake, and sequence comparison of human SLC22A10 were examined in comparison with SLC22A10 from great apes (chimpanzee, bonobo, gorilla and orangutan).

A. This figure shows the plasma membrane localization of SLC22A10 orthologs from great apes, which were conjugated to green fluorescent protein (GFP) in HEK293 cells. The GFP tag is located at the N-terminus of SLC22A10. Confocal imaging revealed that the 552 amino acid isoforms of SLC22A10 from chimpanzee, bonobo, gorilla, and orangutan primarily colocalized with wheat germ agglutinin (WGA) on the plasma membrane of the cell. In contrast, the 540 amino acid isoform of SLC22A10 from bonobo, chimpanzee, and gorilla showed no colocalization of GFP-tagged SLC22A10 with WGA on the plasma membrane, suggesting intracellular localization in the cytoplasm.

B. The uptake of [³H]-estradiol-17β-glucuronide was determined in HEK293 cells overexpressing either a GFP expression vector or SLC22A10 expression vectors containing sequences from various primates including human, chimpanzee, bonobo, gorilla, and orangutan. SLC22A10 orthologs from chimpanzee, bonobo, gorilla, and orangutan expressing the longer isoform (552 amino acids) significantly accumulated [³H]-estradiol-17β-glucuronide. Please refer to the “Statistical Analysis” section for details on the statistical methods used to determine the significance of each cell transfected with the different SLC22A10 orthologs.

C. Sequence alignments of the last exon of SLC22A10 in human, chimpanzee, bonobo, gorilla, and orangutan are shown. In humans, the frequency of the A-allele insertion is significantly greater (98%) than in chimpanzees (2.5%) and is not present in available sequences from bonobos, gorillas, or orangutans. The A-allele insertion results in the expression of human SLC22A10 with 541 amino acids, while bonobo, gorilla, orangutan and the majority of chimpanzees are predicted to express isoforms of SLC22A10 with 552 amino acids.