Question

Describe a pathological condition/ disease that results from a defect in post-translational modification of proteins -----> PLEASE TYPE 250 WORDS & INCLUDE 1 - 2 REFERENCES, NO DIAGRAMS.

Answer 1

Most proteins undergo the process of post translational modification that involves eithe specific cleavage of the polypeptide backbone along with /without changes to the side chains. Some of these modifications might result in pathological disorder or a disease.Defects in Post translation modification that occurs due to mutation in of the post-translational target sites are always directly associated with causing a disease.One such example is a loss of N-linked glycosylation in the prion protein (PRNP).In this case amino acid substitution T183A occurs in the prion protein that leads to autosomal dominant spongiform encephalopathy.This disease is characterised by clinical symptoms such as early-onset dementia, cerebral atrophy, and hypometabolism. In N-linked glycosylation, β-N-acetylglucosamine (GlcNAc) is attached to the side chain of Asn in an AsnXaaSer/Thr group in the prion protein via an amide linkage. This attachements provides the protein with many functions and any modification in this, leads to accumulation of prion proteins thus leading to the pathological conditions.

References:

• LOSS OF POST-TRANSLATIONAL MODIFICATION SITES IN DISEASE: SHUYAN LI, LILIA M. IAKOUCHEVA, SEAN D. MOONEY, and PREDRAG RADIVOJAC

• Protein Posttranslational Modifications: Roles in Aging and Age-Related Disease:Ana L. Santos * and Ariel B. Lindner