A novel highly pathogenic Alzheimer presenilin-1 mutation in codon 117 (Pro117Ser): Comparison of clinical, neuropathological and cell culture phenotypes of Pro117Leu and Pro117Ser mutations.
A novel presenilin-1 (PS1) mutation (P117S) in an American pedigree is described. We compare clinical, neuropathological and cell culture phenotypes produced by this mutation with another codon 117 mutation that was earlier discovered by our group in a Polish kindred. Both mutations are associated with an unusually severe Alzheimer disease (AD) phenotype, with the onset starting before the third decade of life, rapid disease progression and acute presentation of clinical symptoms. The severity of clinical phenotype was closely correlated with the abundance of pathology: massive deposition of Abeta42 in plaques, severe neurofibrillary degeneration and neuronal loss. When overexpressed in mouse neuroblastoma N2a cells, both mutations caused loss of an ability to promote neurite outgrowth and produced an increase in the ratio of secreted Abeta42/40 amyloid peptides. In stably transfected N2a cell lines only mutant proteins were endoproteolytically cleaved indicating some dependability of this process on the presence of mutation. Taken together, our results show that clinical and cell culture phenotypes produced by these 2 codon 117 mutations are closely related suggesting that the pathogenic action of PS1 may involve effect on neurite outgrowth and endoproteolytic cleavage of the full-length protein. Given the high potency in vivo and in vitro of both codon 117 mutations, this site of PS1 must be particularly important for its normal/pathogenic function.
Institute for Basic Research in Developmental Disabilities, Staten Island, New York 10314, USA. k.dowjat@worldnet.att.net
Wieslaw K
WK
Dowjat
Izabela
I
Kuchna
Thomas
T
Wisniewski
Jerzy
J
Wegiel
D000328:Adult; D000544:Alzheimer Disease / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology; D019943:Amino Acid Substitution / Q000235:genetics*; D016564:Amyloid beta-Protein Precursor / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000473:pathology; D045744:Cell Line, Tumor; D003062:Codon / Q000235:genetics*; D018450:Disease Progression; D005260:Female; D015870:Gene Expression / Q000502:physiology; D005838:Genotype; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D051379:Mice; D008875:Middle Aged; D020125:Mutation, Missense / Q000235:genetics*; D016501:Neurites / Q000473:pathology; D009447:Neuroblastoma; D016874:Neurofibrillary Tangles / Q000235:genetics / Q000473:pathology; D009460:Neurologic Examination; D010375:Pedigree; D010641:Phenotype; D053764:Presenilin-1; D011392:Proline / Q000235:genetics*; D012694:Serine / Q000235:genetics*; D014162:Transfection; D014407:Tumor Cells, Cultured / Q000473:pathology
D016564:Amyloid beta-Protein Precursor; D003062:Codon; D008565:Membrane Proteins; C508853:PSEN1 protein, human; D053764:Presenilin-1; D012694:Serine; D011392:Proline