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Proteomics. 2011 Oct;11(20):4047-62. doi: 10.1002/pmic.201100075. Epub 2011 Aug 30.

Identification and validation of mouse sperm proteins correlated with epididymal maturation.

Author information

1
Center for Research on Reproduction and Women's Health, Department of Obstetrics and Gynecology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6080, USA.

Abstract

Sperm need to mature in the epididymis to become capable of fertilization. To understand the molecular mechanisms of mouse sperm maturation, we conducted a proteomic analysis using saturation dye labeling to identify proteins of caput and cauda epididymal sperm that exhibited differences in amounts or positions on two-dimensional gels. Of eight caput epididymal sperm-differential proteins, three were molecular chaperones and three were structural proteins. Of nine cauda epididymal sperm-differential proteins, six were enzymes of energy metabolism. To validate these proteins as markers of epididymal maturation, immunoblotting and immunofluorescence analyses were performed. During epididymal transit, heat shock protein 2 was eliminated with the cytoplasmic droplet and smooth muscle γ-actin exhibited reduced fluorescence from the anterior acrosome while the signal intensity of aldolase A increased, especially in the principal piece. Besides these changes, we observed protein spots, such as glutathione S-transferase mu 5 and the E2 component of pyruvate dehydrogenase complex, shifting to more basic isoelectric points, suggesting post-translational changes such dephosphorylation occur during epididymal maturation. We conclude that most caput epididymal sperm-differential proteins contribute to the functional modification of sperm structures and that many cauda epididymal sperm-differential proteins are involved in ATP production that promotes sperm functions such as motility.

PMID:
21805633
PMCID:
PMC3517136
DOI:
10.1002/pmic.201100075
[Indexed for MEDLINE]
Free PMC Article

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