Gcn4 is a protein kinase that can phosphorylate and inactivate the initiation factor eIF2. The Gcn4 mRNA contains several short upstream open reading frames (uORFs) that negatively regulate its translation initiation. The phosphorylation of eIF2 by Gcn4, therefore, can control Gcn4 expression …
A) in a negative feedback loop.
B) in a positive feedback loop.
C) in a feed-forward loop.

Question

Quizplus · Accepted Answer

Since phosphorylated eIF2 promotes the skipping of the uORFs in favor of the translation of the main Gcn4 ORF, the kinase activity of Gcn4 provides a possible positive feedback control mechanism.

Gcn4 Is a Protein Kinase That Can Phosphorylate and Inactivate