The role of proteomics in understanding sperm cell biology.

The advent of enhanced methods for the pre-fractionation of proteins, improved high speed, high resolution, high sensitivity mass spectrometry hardware and superior informatics/bioformatics software is heralding a new era in our capacity to analyse the proteomic composition of human spermatozoa. Parallel improvements in our capacity to compare proteomic profiles from spermatozoa in different functional states (immature vs. mature, uncapacitated vs. capacitated, normal vs. defective) is also helping to define which specific elements of the proteome are of functional significance. The ultimate aim of such studies will be to integrate the proteome with the sperm metabolome so that we shall not only understand the cascade of post-translational modifications (e.g., phosphorylation, glycosylation, proteolytic cleavage) involved in generating a functional spermatozoon but also determine how these physiological changes are brought about. This fundamental information will then create a basis for identifying key points in the post-testicular maturation of spermatozoa that might be targeted for contraceptive purposes or implicated in the defective sperm function observed in a significant proportion of infertile males.