Bad Dog

It was a bad dog. An unruly one, to say the least. No matter how the scientists tried, IGFBP-5 just wouldn't behave properly. They tried gene knock-outs, knock-downs, and morphelino-RNA. But to no avail. First IGFBP-5 wouldn't stop carrying insulin around. And then it wouldn't pick it back up, unless it wanted to. IGFBP-5 never followed any commands. One moment it would be bound to the extracellular matrix, the next it would be bound to cell-surface integrins or in the nucleoplasm.
And the mess it left behind! In some places it would stimulate cell proliferation, in others cell motility. And then in yet other places it would inhibit those very same things!
Ultimately, researchers concluded that IGFBP-5 wasn't a dog, but a mule.