Linked Life Data

19462288

Source:http://linkedlifedata.com/resource/pubmed/id/19462288

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2009-5-22
pubmed:abstractText
Extracellular ATP has been implicated in a number of cellular events, including mammalian sperm function. The complement of ATP-dependent sperm proteins includes six subunits of the 26S proteasome, a multi-subunit protease specific to ubiquitinated substrate-proteins. Proteolysis of ubiquitinated proteins by the 26S proteasome is necessary for the success of mammalian fertilization, including but not limited to acrosomal exocytosis (AE) and sperm-zona pellucida (ZP) penetration. The 26S proteasome is uniquely present on the sperm acrosomal surface during mammalian, ascidian, and invertebrate fertilization. The proteasome is a multi-subunit protease complex of approximately 2 MDa composed of the 19S regulatory complex and a 20S proteolytic core. Integrity of the 19S complex is maintained by six 19S ATPase subunits (PSMC1 through PSMC6). Consequently, we hypothesized that fertilization will be blocked by the depletion of sperm-surface associated ATP (ssATP). Depletion of ssATP by the Solanum tuberosum apyrase, a 49 kDa, non-cell permeant enzyme, significantly reduced the ATP content measured by an adapted luminescence-ATP assay from which all permeabilizing agents were excluded. Addition of active apyrase to porcine in vitro fertilization (IVF) medium caused a concentration dependent reduction in the overall fertilization rate. No such outcomes were observed in control groups using heat-inactivated apyrase. Apyrase treatment altered the band pattern of 19S ATPase subunits PSMC1 (Rpt2) and PSMC4 (Rpt3) in Western blotting, suggesting that it had an effect on the integrity of the sperm proteasomal 19S complex. Apyrase only altered the proteasomal core activities slightly, since these activities are not directly dependent on external ATP. In contrast, sperm treatment with MG132, a specific inhibitor of the proteasomal core chymotrypsin-like activity, inhibited the target proteolytic activity, but also induced a compensatory elevation in proteasomal peptidyl-glutamyl peptide hydrolase activity. Altogether, the present data provide an important missing piece of evidence in support of the ssATP-dependent, proteasomal-proteolytic model of sperm-ZP interactions.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
1939-6376
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
55
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
85-96
pubmed:dateRevised
2009-11-17
pubmed:meshHeading
pubmed:articleTitle
Sperm-surface ATP in boar spermatozoa is required for fertilization: relevance to sperm proteasomal function.
pubmed:affiliation
Division of Animal Sciences, University of Missouri-Columbia, Columbia, MO 65211-5300, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't