The ApoE Synaptic Formation and Signaling Pathway Antibody Sampler Kit provides an economical means of detecting key synaptic signaling pathways in response to ApoE-mediated LRP1 activation by western blot. The kit includes enough antibodies to perform at least two western blot experiments with each primary antibody.
Specificity / Sensitivity
Each total antibody in the ApoE Synaptic Formation and Signaling Pathway Antibody Sampler Kit detects endogenous levels of its target protein. LRP1 (E2Q7S) Rabbit mAb detects endogenous levels of the β subunit of LRP1. ApoE (pan) (D7I9N) Rabbit mAb also recognizes overexpressed ApoE2, ApoE3, and ApoE4 proteins. CREB (48H2) Rabbit mAb does not cross-react with other ATF/CREB family members. The antigen for Synapsin-1 (D12G5) XP® Rabbit mAb is 100% conserved between human synapsin-1a and synapsin-1b. Each phospho-specific antibody in the ApoE Synaptic Formation and Signaling Pathway Antibody Sampler Kit detects endogenous levels of CREB only when phosphorylated at Ser133, PSD95 protein only when phosphorylated at Ser295, and AMPA Receptor 1 (GluA1) protein only when phosphorylated at Ser831. Phospho-CREB (Ser133) (87G3) Rabbit mAb also detects the phosphorylated form of the CREB-related protein, ATF-1. While Phospho-AMPA Receptor 1 (GluA1) (Ser831) (A5O2P) Rabbit mAb refers to Ser831, consistent with the literature, it is Ser849 in the UniProt sequence P42261.
Source / Purification
Monoclonal antibodies to total proteins are produced by immunizing animals with synthetic peptides corresponding to residues surrounding Leu4488 of human LRP1 protein, Pro285 of human ApoE protein,Gln53 of human PSD95 protein, Gln483 of human synapsin-1 protein, Ala275 of human AMPA Receptor 1 (GluA1) protein, and recombinant protein specific to the amino terminus of human CREB-1 protein. Phospho-specific monoclonal antibodies are produced by immunizing animals with synthetic phosphopeptides corresponding to residues surrounding Ser295 of human PSD95 protein, Ser831 of human AMPA Receptor 1 (GluA1) protein, and Ser133 of human CREB protein.
Low density lipoprotein receptor related protein 1 (LRP1) is a type I transmembrane receptor that mediates the endocytosis of various ligands, including apolipoproteins and tau. Both proteins are genetically and pathologically linked to Alzheimer’s disease (AD) (1,2). Human apolipoprotein E (ApoE) is a component of circulating lipoproteins when three human genetic ApoE variants, ApoE2, ApoE3, and ApoE4, exhibit distinct receptor-binding properties and differentially contribute to AD progression through a cellular mechanism that is poorly understood (2). Altered synaptic signaling is one proposed mechanism that contributes to altered neuronal function, which correlates with disease (3-5). Postsynaptic Density protein 95 (PSD95) is a member of the membrane-associated guanylate kinase (MAGUK) family of proteins that functions as a scaffolding protein to promote assembly and function of the postsynaptic density complex (6,7). At the presynapse, synapsins function to regulate neurotransmitter release (8,9). Dynamic phosphorylation of PSD95 at Ser295 reflects synaptic signaling that may alter synaptic function (10). In addition to PSD95, postsynaptic glutamate receptors, including AMPA-(α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptors, can be directly phosphorylated. Phosphorylation of AMPA Receptor 1 (GluA1) at either Ser831 or Ser845 alters AMPA receptor ion channel function to change synaptic efficacy (11). CREB is a bZIP transcription factor that activates target genes through cAMP response elements. CREB is activated by phosphorylation at Ser133 by various signaling pathways including Erk, Ca2+,stress signaling, as well as synaptic signaling (3).