Time filter

Source Type

Korrodi-Gregorio L.,University of Aveiro | Ferreira M.,University of Aveiro | Vintem A.P.,University of Aveiro | Wu W.,University of Aveiro | And 7 more authors.
BMC Cell Biology | Year: 2013

Background: Protein Ser/Thr Phosphatase PPP1CC2 is an alternatively spliced isoform of PPP1C that is highly enriched in testis and selectively expressed in sperm. Addition of the phosphatase inhibitor toxins okadaic acid or calyculin A to caput and caudal sperm triggers and stimulates motility, respectively. Thus, the endogenous mechanisms of phosphatase inhibition are fundamental for controlling sperm function and should be characterized. Preliminary results have shown a protein phosphatase inhibitor activity resembling PPP1R2 in bovine and primate spermatozoa.Results: Here we show conclusively, for the first time, that PPP1R2 is present in sperm. In addition, we have also identified a novel protein, PPP1R2P3. The latter was previously thought to be an intron-less pseudogene. We show that the protein corresponding to the pseudogene is expressed. It has PPP1 inhibitory potency similar to PPP1R2. The potential phosphosites in PPP1R2 are substituted by non-phosphorylable residues, T73P and S87R, in PPP1R2P3. We also confirm that PPP1R2/PPP1R2P3 are phosphorylated at Ser121 and Ser122, and report a novel phosphorylation site, Ser127. Subfractionation of sperm structures show that PPP1CC2, PPP1R2/PPP1R2P3 are located in the head and tail structures.Conclusions: The conclusive identification and localization of sperm PPP1R2 and PPP1R2P3 lays the basis for future studies on their roles in acrosome reaction, sperm motility and hyperactivation. An intriguing possibility is that a switch in PPP1CC2 inhibitory subunits could be the trigger for sperm motility in the epididymis and/or sperm hyperactivation in the female reproductive tract. © 2013 Korrodi-Gregório et al.; licensee BioMed Central Ltd. Source

Ferreira M.,University of Aveiro | Silva J.V.,University of Aveiro | Silva V.,Center for Fertility Studies | Barros A.,University of Aveiro | And 2 more authors.
Asian Pacific Journal of Reproduction | Year: 2012

Objective: To investigate the impact of acute lifestyle changes on human sperm functional quality. Methods: In the academic festivities week, young and apparently healthy male students who voluntarily submit themselves to acute lifestyle alterations (among the potentially important variations are increase in alcohol, caffeine, and tobacco consumption and circadian rhythm shifts) were used as a model system. Sperm samples were obtained before and after the academic week and compared by traditional semen analysis (n=54) and also tested for cleaved Poly ADP-ribose polymerase (PARP) protein, an apoptotic marker (n=35). Results: Acute lifestyle changes that occurred during the academic week festivities (the study model) resulted both in a significant reduction in sperm quality, assessed by basic semen analysis (decrease in sperm concentration, total number of spermatozoa, progressive and non-progressive motility and increase in sperm morphological abnormalities) and by an increase in the expression of the apoptotic marker, cleaved PARP, in the ejaculate. Conclusions: Acute lifestyle changes have clear deleterious effects on sperm quality. We propose cleaved PARP as a novel molecular marker, valuable for assessing sperm quality in parallel with the basic semen analysis method. © 2012 Hainan Medical College. Source

Discover hidden collaborations