Abstract
Purpose::
It has been demonstrated that the human immunodeficiency virus (HIV) uses an interaction between Basigin, a membrane glycoprotein on CD4+ T cells, and cyclophilin A (CyPA) on the viral capsid for infection. CyPA is a peptidyl-prolyl cis-trans isomerase, a chaperone protein. Both of these proteins are also present in the mammalian retina. We therefore sought to determine whether the retina forms of the proteins also interact.
Methods::
Histidine-tagged recombinant proteins of CyPA and the transmembrane domain of Basigin were generated for these studies. Sandwich ELISAs were performed in which endogenous retina proteins (either CyPA or Basigin) were captured and probed with the complementary Histidine-tagged recombinant protein.
Results::
It was determined that indeed, the Basigin transmembrane domain interacts with endogenous retina CyPA. Surprisingly, another membrane protein known to interact with Basigin in the retina, Monocarboxylate transporter-1 (MCT1), also binds to CyPA in sandwich ELISAs.
Conclusions::
Previous reports have suggested that Basigin acts as a chaperone protein required to translocate MCT1 to the plasma membrane of cells. This new data suggests that CyPA, not Basigin, is the chaperone protein that transports both proteins to the cell surface.
Keywords: protein structure/function • cell-cell communication