Which of the following statements is correct concerning ubiquitin?
A) Ubiquitin occurs only in liver cells.
B) Covalent coupling of ubiquitin to a protein can mark that protein for degradation.
C) It is involved in transfer of mannose-rich oligosaccharides to proteins.
D) It is a transcription factor for RNA polymerase II.
E) it is an snRNP necessary for splicing of mRNA precursors.

Question

Quizplus · Accepted Answer

Covalent coupling of ubiquitin to a protein is a well-known mechanism for marking that protein for degradation by the proteasome. This process, known as ubiquitination, plays a key role in regulating protein turnover and maintaining cellular homeostasis. The other options are not correct as ubiquitin is not specific to liver cells (A), is not involved in transfer of mannose-rich oligosaccharides to proteins (C), is not a transcription factor for RNA polymerase II (D), and is not an snRNP necessary for splicing of mRNA precursors (E).

Which of the Following Statements Is Correct Concerning Ubiquitin