Differential distribution of Alzheimer's amyloid precursor protein family variants in human sperm.
The Alzheimer's amyloid precursor protein (APP) is a type I transmembrane glycoprotein with receptor-like characteristics that originates the Abeta peptide by proteolytic processing. Abeta is potentially cytotoxic and the major component of the cerebral amyloid plaques in Alzheimer's disease (AD) patients. APP is known to be ubiquitously expressed in mammalian cells, with a broad tissue distribution, and Abeta deposition has been reported to occur also in many cells outside the nervous system. Although many putative functions have been suggested for APP, its precise physiological role remains to be elucidated. As several results point to a role of chronic inflammation in AD pathogenesis and suggest that AD might be a systemic disorder, the importance of APP function in non-neuronal cells/tissues has gained increased relevance. Previous studies have shown that amyloid precursor-like protein 2 (APLP2) is highly expressed in testis and sperm, but failed to unambiguously prove the presence of APP itself in mammalian sperm. The use of a battery of available antibodies that detect APP-specific epitopes or epitopes shared with other APP family members, revealed quite distinct distributions in human sperm. Our results are consistent with previous observations of APLP2 in sperm and unequivocally demonstrate the presence of APP itself in human sperm, thus suggesting a putative role for this important protein in sperm function.
Fardilha
Margarida
M
Signal Transduction Laboratory, Centre for Cell Biology, University of Aveiro, Aveiro, Portugal.
Vieira
Sandra I
SI
Barros
Alberto
A
Sousa
Mário
M
Da Cruz e Silva
Odete A B
OA
Da Cruz e Silva
Edgar F
EF
D016229:Amyloid beta-Peptides / Q000096:biosynthesis*; D016564:Amyloid beta-Protein Precursor / Q000096:biosynthesis*; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D000939:Epitopes / Q000737:chemistry; D005786:Gene Expression Regulation; D016678:Genome; D006801:Humans; D008297:Male; D008954:Models, Biological; D009419:Nerve Tissue Proteins / Q000096:biosynthesis*; D013094:Spermatozoa / Q000378:metabolism*; D013737:Testis / Q000378:metabolism
C084104:APLP2 protein, human; D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D000939:Epitopes; D009419:Nerve Tissue Proteins