Apoe3 Isoforms

Proteins are important to human physiology and play an essential role in bodily function. Isoforms of proteins can result in increased susceptibility to many diseases. One such isoform can be observed in the polymorphic protein APO-E, which exists in the ApoE2, ApoE3, and ApoE4 isoforms (Mahley and Rall, 2000). The most common isoform is ApoE3, which is considered the normal isoform for the known physiology of APOE. APOE plays a role in transporting and metabolizing plasma cholesterol and triglycerides by interacting with low density lipoproteins and their respective receptors. (Han et al., 2003). In the central nervous system ApoE that is mainly synthesized in astrocytes, aids in the transportation and redistribution of lipids and cholesterol. ApoE is particularly crucial to the nervous system because of its ability to act as a target protein for the redistribution of cholesterol in neural tissue that is undertaking repair. (Siest et al., 1995). …show more content…
(Siest et al., 1995). ApoE3 influences the clearance of amyloid-B peptides, therefore preventing amyloid-B peptide deposits (Mahley and Rall, 2000). Nevertheless, the ApoE4 is one of the dysfunctional isoforms of the protein and can evidently increase one’s susceptibility to late-onset of Alzheimer’s disease. One of the first evidences of identifying ApoE4 as a probable risk factor in Alzheimer’s Disease came from Shimano et al., who found a “twofold greater relative frequency of the E4 allele in AD pateints” (Siest et al., 1995). Later, Namba et al. (1991, p.163) conducted immunohistochemical experiments in patients with Alzheimers disease using antibodies to ApoE. Through ApoE immunoreactivity, the localization of ApoE4 protein in amyloid plaques and neurofibrillary tangles in patients with Alzheimer’s Disease was observed. (Namba et al.,