Fig. 5: Interfering peptide blocks CDYL phosphorylation at Ser147, elevating CDYL levels and impairing contextual fear memory in mice.
From: Activity-dependent phosphorylation of CDYL by CDK5 regulates fear memory in mice
A, B Construction of interfering peptides: a peptide mimicking the sequence near Ser147 was synthesized and fused to the Tat cell-penetrating peptide (Tat-S147). A control peptide with Ser147 mutated to alanine (Tat-S147A) was similarly constructed (A). Both peptides were additionally tagged with FITC for visualization (B). C In vitro 32P radioautography assay: purified His-CDK5 and GST-CDYL 61-180 were incubated in the presence of 32P-labeled ATP and treated with TAT-S147A or TAT-S147 as indicated. D-G Localization and relative levels of FITC-tagged interfering peptide in the hippocampus: FITC signal intensity assessed at 1 h (D), 3 h (E), 6 h (F), and 12 h (G) post-injection. The distribution of FITC signal was matched to coronal section of mouse brain at Bregma -2.06 mm. Scale bars: 800 μm (left), 50 μm (right). H, I Protein levels of CDYL and p-CDYL in mouse hippocampus: post-treatment with Tat-S147 and Tat-S147A (Unpaired t-test, n = 3 each for Tat-S147A, Tat-S147). J Diagram of peptide injection via cannula and fear conditioning test. K Contextual fear conditioning test results: mice treated with Tat-S147 or Tat-S147A (Unpaired t-test, n = 13 for Tat-S147A, 11 for Tat-S147). L Location and signals of peptides three hours after being injected into the hippocampus: Scale bar: 700 μm. All data are represented as mean ± SEM. *p < 0.05.
