Effects of Mutations on Protein Function
Start with the big picture
The impact of a mutation depends on what it changes and where. A point mutation may be silent, missense, or nonsense; missense effects can range from minimal to severe depending on the amino acid change and its location. Frameshifts and splice-site disruptions can alter the downstream sequence or produce abnormal transcripts. Other mutations affect transcription, translation initiation, or mRNA processing, changing protein quantity without necessarily changing its sequence. In-frame insertions or deletions and trinucleotide repeat expansions have distinct effects. The lesson also connects mutation mechanisms to functional outcomes, including loss of function, gain of function, and dominant-negative activity, with examples such as CFTR, Huntingtin, FMR1, p53, and BCR-ABL.
What you'll learn
- Classify point mutations as silent, missense, or nonsense.
- Explain how frameshift and splice-site mutations can alter protein products.
- Distinguish mutations that change protein sequence from those that alter protein abundance.
- Compare loss-of-function, gain-of-function, and dominant-negative effects.
- Relate selected mutation types to examples such as CFTR, p53, and BCR-ABL.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
