Integral Membrane Protein 1 (ITM1)

The amino acid sequence of the human B5 was 98.5% identical to that of the mouse protein. A striking feature of the B5 protein was the presence of numerous (10 to 14) potential transmembrane domains, characteristic of an integral membrane protein. Similarity searches in public databases revealed that B5 is 58% similar to the T12A2.2 gene of C. elegans and 60% similar to the STT3 gene of S. cerevisiae.

The predicted 705-amino acid protein has 13 putative transmembrane domains. Northern blot analysis revealed that the gene is expressed in a variety of human tissues, with highest expression in ovary and testis. Northern blot and RT-PCR analysis showed no differences in the level of expression among normal and malignant mesothelial cell lines tested.