Like many milestone discoveries, heat shock proteins (HSPs) were discovered by accident. In 1962, the Italian scientist Ferruccio Ritossa was studying fruit fly genetics, when one morning he found his incubator to be set at a temperature higher than normal. Ritossa amusingly denied responsibility for the mistake, even in his write-up of his finding.  He says "I do not remember whether it was John Pulitzer or Inge or Clara Ghini and Giordano who shifted the temperature of my incubator, but one day I noticed a different puffing pattern!"[1] A “puffing pattern” is seen under a microscope when a gene is being transcribed. Those genes were transcribing heat shock proteins, although it would be years before we would know that, and decades before we would know the real significance of that discovery. In fact, we are still discovering the full significance of his discovery. 

Proteins 101

Before we dive in, let’s make sure we are on the same page, with a brief recap on proteins.  What exactly are proteins? Like, a side of chicken? Smaller. We are diving into the cells of that chicken—the microscopic cells that make up every tissue and organ in your body.
Our cells are crowded places. They are not the clean, spacious line drawing from your high school biology textbook, with a nucleus and mitochondrion separated by a white page, substrates moseying over in a leisurely backstroke.  Each of our cells can contain billions of proteins, doing thousands of different jobs.  That line drawing was a bit simplified, of course.  Our cells are astoundingly busy and complex micro-verses.