Research ArticleNeurodegeneration

Gain-of-function mutations in protein kinase Cα (PKCα) may promote synaptic defects in Alzheimer’s disease

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Science Signaling  10 May 2016:
Vol. 9, Issue 427, pp. ra47
DOI: 10.1126/scisignal.aaf6209
  • Fig. 1 Synaptic depression by Aβ blocked by uncompetitive PKC antagonist.

    (A and B) Top left: Experimental design (see Materials and Methods). Plots (A) and bar graphs (B) of evoked synaptic response amplitudes recorded in CT100-infected versus noninfected neurons. Shown are individual (black) and average (red) of cell pair responses; sloped line, x = y. Sample traces (B, right) obtained from indicated conditions. Scale bars, 50 ms, 50 pA. Data are means ± SEM from 12 to 13 pairs of cells (one infected, the other not); **P < 0.03, by bootstrap test (see Materials and Methods). (C) Normalized average of PKC activity in COS7 cells expressing PKC activity reporter CKAR (C kinase activity reporter) fused to PSD95 (left) or targeted to plasma membrane (right) in response to the competitive (Gö 6983) or uncompetitive (Bis IV) PKC inhibitor, added at the time indicated by the arrow head. Data are means ± SEM from >16 cells; ****P < 0.0001, by bootstrap test (see Materials and Methods); n.s., not significant.

  • Fig. 2 PKCα is required for the effects of Aβ on synaptic transmission.

    (A and B) Plot (A), and example traces (bottom right), of evoked synaptic response amplitudes recorded in infected versus noninfected neurons; genotype and infection indicated. Bar graph (B, left) of same data. **P < 0.03, by bootstrap test (see Materials and Methods). wt, wild-type.

  • Fig. 3 Human genetics of rare PKCα variants.

    Diagrams indicating number of families, along with phenotype and genotype of individuals, carrying M489V, V636I, or R324W PKCα variants. All PKCα variant carriers (yellow) displayed AD, and both individuals without AD (blue) lacked a PKCα variant.

  • Fig. 4 AD-associated rare variants in PKCα.

    (A) PKCα kinase domain structure (53) showing two residues altered in AD:Met489 and Val636. Both are near key regulatory phosphorylation sites (stick representation). Enlargement of activation loop segment (right panels) showing that substitution of Met489 with Val loosens the structural packing of this segment. (B) Western blot showing phosphorylation of the indicated hemagglutinin (HA)–tagged PKCα proteins. (C) Western blot of COS7 cells expressing wild-type or M489V PKCα and treated with phorbol 12,13-dibutyrate (PDBu) for the indicated times and probed for HA. Quantitative analysis of phosphorylated/total PKC from five independent experiments. **P < 0.01, by bootstrap test (see Materials and Methods).

  • Fig. 5 Live-cell imaging reveals higher signaling output of all three AD-associated rare variants.

    Left: Normalized FRET ratios (mean ± SEM) representing PKC activity in COS7 cells coexpressing PKC activity reporter, CKAR, (22) and indicated PKCα. Addition of uridine 5′-triphosphate (UTP) (100 μM) where indicated (arrow head). n > 25 cells for each construct. Data are means ± SEM from at least three independent experiments. Right: Area under the curve from 3 to 6 min; *P < 0.05, by bootstrap test (see Materials and Methods). r.u., relative units.

Supplementary Materials

  • Supplementary Materials for:

    Gain-of-function mutations in protein kinase Cα (PKCα) may promote synaptic defects in Alzheimer's disease

    Stephanie I. Alfonso, Julia A. Callender, Basavaraj Hooli, Corina E. Antal, Kristina Mullin, Mathew A. Sherman, Sylvain E. Lesné, Michael Leitges, Alexandra C. Newton,* Rudolph E. Tanzi,* Roberto Malinow*

    *Corresponding author. Email: anewton{at}ucsd.edu (A.C.N.); tanzi{at}helix.mgh.harvard.edu (R.E.T.); rmalinow{at}ucsd.edu (R.M.)

    This PDF file includes:

    • Fig. S1. Aβ abundance in brain slices infected with virus producing CT100 is similar in wild-type and PRKCA−/− slices.
    • Fig. S2. Pedigree charts of the NIMH families found to carry rare PKCα variants.

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    Citation: S. I. Alfonso, J. A. Callender, B. Hooli, C. E. Antal, K. Mullin, M. A. Sherman, S. E. Lesné, M. Leitges, A. C. Newton, R. E. Tanzi, R. Malinow, Gain-of-function mutations in protein kinase Cα (PKCα) may promote synaptic defects in Alzheimer's disease. Sci. Signal. 9, ra47 (2016).

    © 2016 American Association for the Advancement of Science

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