If you forgot to add the zip code to a letter, would it still reach the correct destination? Eventually it should, thanks to the US Postal Service and the other address information. Cells also need to ensure their messages reach the correct destinations, and a recent paper in Molecular Biology of the Cell reveals that, just like the post office, cells use multiple layers of information to target messenger RNA transcripts (mRNAs) to an important cellular address.
Every cell in the body starts off with essentially the same genome, but sometimes the DNA sequence in a cell gets changed. Some of these changes are due to normal physiology (e.g. DNA is rearranged in immune cells to generate diversity in the adaptive immune system), but others are actual errors that occur when the DNA is copied during cell base. Some mistakes involve the introduction of long sequences in which short DNA "words" are repeated many times. Like a skipping CD (or an old school vinyl record), small areas of the genome are repeated over and over again and once it's copied in the DNA, all subsequent cellular offspring, have the repeated mistake.
Protein aggregates—abnormal clumps of misfolded proteins—are common feature in diseases such as Parkinson's, Huntington's, and Creutzfeldt-Jakob (CJD, the infamous "mad cow" disease). However, it's still a mystery as to whether these aggregates cause the disease or are simply an effect. If aggregates are the cause, how do they work?