You are studying the consequences of carbohydrate modification of proteins in hepatocyte cultures. Your studies reveal that addition of high levels of glucose to the culture system results in modification and activation of the transcription factor PGC-1α, leading to an increased rate of gluconeogenesis. Which of the following is the most likely modification that results in the observed activation of PGC-1α?
A) N-glycosylation
B) O-GlcNAcylation
C) O-glycosylation mucin type
D) O-mannosylation

Question

Quizplus · Accepted Answer

O-GlcNAcylation is a type of carbohydrate modification that involves the addition of N-acetylglucosamine to serine or threonine residues of nuclear and cytoplasmic proteins, and it is known to regulate protein function, including transcription factors like PGC-1α. Hyperglycemia is associated with O-GlcNAcylation of transcription factors and cofactors such as FOXO1, FOXO3, CREB-regulated transcription coactivator 2 (CRTC2), and PGC-1α that are involved in the modulation of the expression of gluconeogenic genes. PGC-1α is a key transcriptional coactivator that regulates mitochondrial biogenesis as well as hepatic gluconeogenesis. Under euglycemic conditions,O-GlcNAc transferase (OGT) activation leads to O-GlcNAcylation of PGC-1α and expression of gluconeogenic genes.

You Are Studying the Consequences of Carbohydrate Modification of Proteins