Global Profiling of Surface Plasma Membrane Proteome of Oviductal Epithelial Cells

In mammalian reproduction, many important events occur within the female reproductive tract,
especially within the oviduct. These include transport and final maturation of the female and male
gametes, fertilization, embryonic development, and transport of the embryo to the uterus. The plasma
membrane molecules of oviductal epithelia that are in direct contact with gametes and embryo(s) and
potentially mediate these processes are poorly characterized, and their function is poorly understood.
Defining the oviductal cell surface proteome could provide a better understanding of the basis of
reproductive processes taking place within the oviduct. We aimed to provide a detailed profile of the
surface plasma membrane proteome of the oviductal epithelium by biotinylation of proteins at the cell
surface, followed by highly specific purification of these proteins using avidin. This approach for
enrichment of oviductal cell surface proteome was validated by immunohistochemistry, gel electrophoresis, and western blot analysis experiments. The enriched molecules were identified using two
different technologies:  (i) the combination of 2D gel electrophoresis with mass spectrometry and (ii)
1D gel electrophoresis with mass spectrometry (a modified multidimensional protein identification
technology (MudPIT) technique). The number of proteins identified using the MudPIT approach was
approximately 7 times the number of proteins identified by 2D gel electophoresis using the same
samples (40 versus 276, respectively). Some of the proteins found at the surface of oviductal cells had
previously been reported as present in the oviduct and to have known functions in relation to
reproductive processes. The other category of proteins that were highly represented in the oviductal
surface proteome were various members of the family of heat-shock proteins. To the best of our
knowledge, this is the first comprehensive study to identify and characterize proteins at the surface of
the epithelium of the mammalian oviduct.
Keywords: reproduction • oviductal epithelium • surface proteome • biotinylation