Scavenger receptor A5 (SCARA5, also known as testis expressed scavenger receptor Tesr) is a Class A scavenger receptor that is related to CL-P1, MARCO, SCARA3, and SR-A1. All are type II transmembrane proteins that contain a collagenous stalk (1-3). Mature mouse SCARA5 consists of a 60 amino acid (aa) cytoplasmic domain, a 21 aa transmembrane segment, and a 410 aa C-terminal extracellular domain (ECD) that contains a coiled-coil, a collagen-like, and a scavenger receptor cysteine-rich (SRCR) region (4, 5). Within the ECD, mouse SCARA5 shares 87% and 98% aa sequence identity with human and rat SCARA5, respectively. It shares 24%-29% aa sequence identity with CL-P1, MARCO, SCARA3, and SR-A1. Alternative splicing generates one isoform that lacks the SRCR domain and a second that additionally lacks the cytoplasmic and transmembrane regions. SCARA5 is a cell surface disulfide-linked homotrimer of > 250kD (5). It is highly expressed in testicular Sertoli and germ cells and more weakly in the epithelia of other tissues (4, 5). During mouse development, SCARA5 expression is attenuated in female embryos at the time of sex determination, whereas it is maintained in the developing testis (4). SCARA5 is re-expressed in the adult ovary (4). SCARA5 binds heat-killed bacterial particles but not yeast particles or modified LDL (5). Recombinant protein corresponding to Arg83-Pro491 from mouse SCARA5, fused to 6-His-Tag at N-terminal, expressed in CHO cells. Activity: Measured by its ability to bind Fluorescein conjugated S. aureus Bioparticles. Storage and Stability: Lyophilized and reconstituted products are stable for 6 months after receipt at -20C. Reconstitute with sterile PBS. Aliquot to avoid repeated freezing and thawing. Store at -20C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.
