Throughout the living world, we find amazing examples of something we recognize from our own intelligent designs: quality control.

In industry, quality control may be automated. In Mars rover operation, the vehicle has been pre-programmed to handle contingencies on its own, due to the long delay time in communications with Earth. The better the rover can operate autonomously, the more we rightly admire the skill of the designers. So it is with the cell.

The term "quality control" appears with regularity in scientific papers about the cell. It’s as if the cell knows that it cannot put inferior products out in its marketplace and expect to survive in business. Here are some recent examples.

Damage Control in the ER

"A new quality control pathway in the cell" was announced by the Centre for Genomic Regulation in Spain. It operates in the endoplasmic reticulum (ER), where protein folding is completed before delivery, and where the nuclear envelope is assembled.

• In a paper published today in Science, CRG researchers describe a new protein quality control system in the inner nuclear membrane.
• The new system has two main functions, to eliminate misfolded proteins and to protect the nucleus from accumulating mislocalised (or ectopic) proteins. This may be especially relevant in non-dividing cells such as neurones. (Emphasis added.)

The news release uses the term a third time: "cells have developed quality control systems just like any other production chain or manufacturing process." As if to make sure readers get the point, "quality control" appears seven times in the short article. For example:

Other quality control systems have been described but exactly how misfolded proteins in the inner nuclear membrane were degraded was not known.

The newly identified quality control system protects the nucleus by targeting foreign proteins that could enter the nucleus by mistake.

The writer does not attempt to explain how quality control systems evolved; just that "cells have developed" them.

Mechanical Safeguards in Meiosis

The formation of sex cells by meiosis involves additional steps beyond binary cell division (mitosis). Once again, we find quality control mechanisms ensuring that the correct number of haploid chromosomes get parsed out into the daughter cells. University of Washington Health Sciences subtitles its news item, "Reproductive cell division has a mechanical safeguard against errors." With a hat tip to Darwin, the article claims that meiosis "evolved a simple, mechanical solution to avoid chromosome sorting errors."

During cell division, Adele Marston says, "chromosomes must be precisely sorted in an elaborate choreography where chromosomes pair up and then part in a sequence." There’s zero tolerance for error. Without this mechanical safeguard (or when it fails), wrong numbers of chromosomes could get delivered to the gametes, resulting in "infertility, miscarriage, or congenital conditions."

How is this quality control achieved? Working with baker’s yeast, a simple eukaryote, the senior author Charles Asbury found something like a locking process to ensure chromosomes do not separate prematurely as molecular machines and motors go into action all around them:

In all types of cell division, he noted, sister chromatids are held together at first by cohesion. But in the earlier stages of reproductive cell division, the research team discovered that a strong, extra-tight linkage joins the sister chromatids.

When cells prepare to divide, molecular machines, called kinetochores, show up and assume several roles. They both control and drive chromosome movement. They set the timing for other cell division events, including the actual splitting of the chromosomes.

The kinetochores consist of an array of proteins that bind to the tips of miniscule, fiber-like structures called microtubules. The tips act as motors. The kinetochore converts the lengthening and shortening of the microtubules tips into useful force to move chromosomes.

The researchers determined that, during the early stages of meiosis, kinetochores between sister chromosomes mechanically fuse. The tethering keeps chromosomes from separating prematurely and ending up misplaced.

They identified a protein complex named "monopolin" that acts as the lock. Although the short article didn’t mention it, logic requires that other factors enter this "elaborate choreography" to break the locks in time for the chromosomes to make it into the daughter cells. As a result of this mechanical safeguard, "Cells simply avoid chromosome confusion."

It should be noted that a number of "checkpoints" have been identified in cell division — another stunning example of quality control. Checkpoints are like mandatory inspections with enzymes empowered to make go or no-go decisions, ensuring that all the players are prepared before the show goes on. If a cell fails the checkpoint, the cell will be ordered to commit suicide (programmed cell death) rather than allow defective cells enter the marketplace of the organism.

First Aid Kits in Stem Cells

Imagine a cell that can make a first-aid kit for its offspring. It almost sounds like forethought, but that’s what neural stem cells do, according to the University of Cambridge: "Neural stem cells — master cells that can develop into any type of nerve cell — are able to generate mini ‘first-aid kits’ and transfer them to immune cells, according to a study published today."

The first-aid kits are vesicles: membrane-bound cargo ships that the neural stem cells can send across intercellular space to immune cells. This, we know, is of great interest with all the active research into stem cells for regenerative medicine and therapy for a wide variety of diseases.

The discovery means that stem cells don’t always have to differentiate and become immune cells: they can simply share their information and tools with existing cells. It’s a bit like shipping tools in a package instead of coming over and doing the work in person:

Dr Stefano Pluchino from the Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, who led the study, said: "These tiny vesicles in stem cells contain molecules like proteins and nucleic acids that stimulate the target cells and help them to survive — they act like mini "first aid kits".

"Essentially, they mirror how the stem cells respond to an inflammatory environment like that seen during complex neural injuries and diseases, and they pass this ability on to the target cells. We think this helps injured brain cells to repair themselves."

During an immune response, the immune cells put up receptors for the vesicles on their cell surfaces. When the vesicles arrive, they attach to the receptors and come inside. The immune cells then use the proteins and nucleic acids included in the first-aid kit for self-repair. Other factors switch on genes within the nucleus.

According to Dr. Pluchino, the work "represents a significant advance in understanding the many levels of interaction between stem cells and the immune system, and a new molecular mechanism to explain how stem-cell therapy works."

Hey, Listen to This QC

To avoid deafness, it’s important that the sound-sensing hair cells in mammalian ears get made "in the right place, at the right time." That’s the essence of an item from Johns Hopkins Medicine about two factors, Hey1 and Hey2, which perform this quality control (QC) function:

"The proteins Hey1 and Hey2 act as brakes to prevent hair cell generation until the time is right," says Angelika Doetzlhofer, PhD, an assistant professor of neuroscience. "Without them, the hair cells end up disorganized and dysfunctional."

The article describes how "parent cells" in the developing cochlea differentiate into hair cells in a "precise sequence" under the control of a master regulator called Sonic Hedgehog. When mice were bred without the Hey1 and Hey2 proteins, "the [hair] cells were generated too early and were abnormally patterned: Rows of hair cells were either too many or too few, and their hairlike protrusions were often deformed and pointing in the wrong direction." They could tell by looking that those mice were going to be severely deaf.

By observing the "precise sequence" of events, the scientists were able to observe the quality control system at work:

"Hey1 and Hey2 stop the parent cells from turning into hair cells until the time is right," explains Doetzlhofer. "Sonic Hedgehog applies those ‘brakes,’ then slowly releases pressure on them as the cochlea develops. If the brakes stop working, the hair cells are generated too early and end up misaligned."

Quality control is a concept implying forethought and goal-directed action. An entity desires a quality product, then organizes factors to ensure its delivery. When risks and contingencies threaten, measures are pre-planned to deal with them.

Industry relies on quality control. Whole departments are devoted to it. We’re all familiar with surveys, when companies want to make sure we were satisfied with the product. We know inspectors will show up unannounced at sites to perform random inspections. We know that smart companies plan for emergencies with spare parts and first aid kits. Companies prepare elaborate Policy and Procedure manuals to deal with everything from normal operations to disaster preparedness. We’ve heard of Go/No-Go checkpoints, like in the space program, when before launch, the program manager queries all the system managers: "Propulsion?" "Go!" "Weather?" "Go!" "IT systems?" "Go!" "Fluid pressure?" "Go!" "Perimeter safety?" "Go!" "Launch systems?" "Go!" Only after a rigorous checklist will he say, "We are go for launch."

To see these same kinds of precautions at work in a living cell is uncannily like what we know from industry. From our uniform experience, we recognize QC as the work of intelligence. To say that life uses quality control does not imply that life "developed" it or "evolved" it. That would be like saying the Mars rover evolved its QC systems from the rocks and sands that surround it. Natural selection might explain the survival of QC, but it cannot explain the arrival of QC. That took intelligent design.