Prestin

Booking photographs

The suspect, from its real atomic coordinates. Drag to turn it. Height chart in nanometers, a line every 2 nm. A grown bottlenose dolphin is about 300 million times longer.

Rap sheet

1. Moving without fuel of its own: changes its footprint in the membrane with voltage, no ATP.
2. Speeding: clocked at 79,000 cycles a second by one lab (1999); disputed by another.
3. Convergence: bats and dolphins, both echolocators, arrived at the same prestin change independently.
4. Misfiling: its gene tree puts the dolphin among bats instead of next to the cow.
5. Quitting the family business: its chicken and zebrafish cousins swap anions; the mammalian one moves instead.

Answers to

Prestin, from presto (fast). Alias SLC26A5.

Height

11 nm. Twins, side by side in a membrane.

Weight

270 zeptograms for two.

Habits

Swells and shrinks with voltage. No ATP.

Speed

Clocked at 79,000 cycles a second by one lab. Disputed by another.

Associates

Echolocating bats. Prestin’s tree puts dolphins with them, not cows.

Marks

Thr at position 7, like every echolocating mammal checked. Yours: Asn.

Last seen

Frozen in ice under an electron microscope, in a lab in Chicago.

M.O.

A bound anion and the charged residues around it act as a voltage sensor. When the hair cell's membrane potential swings, the protein's area in the membrane changes; millions of copies together lengthen and shorten the cell, cycle by cycle.

Associates

echolocating bats (threonine at position 7); the bottlenose dolphin (threonine at position 7); the stria vascularis, which keeps the inner ear's battery charged; its anion-swapping cousins in chickens and zebrafish

Priors

Named in 2000 for presto; electromotility clocked to at least 79 kHz in 1999 (disputed); the bat and dolphin convergence reported in 2010; cryo-EM structures in 2021.

of them in one outer hair cell of a mouse, give or take.
Nobody has counted a dolphin’s. You’ve never seen one.

“No receipts in its pockets. They were next door.” — Keltar, on the case