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Unraveling Entropic Rate Acceleration Induced by Solvent Dynamics in Membrane Enzymes

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Published on: January 16, 2016

PIN proteins perform a rate-limiting function in cellular auxin efflux.

Jan Petrásek¹, Jozef Mravec, Rodolphe Bouchard

¹Institute of Experimental Botany, the Academy of Sciences of the Czech Republic, 165 02 Prague 6, Czech Republic.

Science (New York, N.Y.)

|April 8, 2006

Summary

Pin-formed (PIN) proteins directly catalyze cellular auxin efflux, a vital plant hormone transport process. This study reveals PINs function independently of other plant factors, clarifying their role in development.

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Area of Science:

Plant Biology
Molecular Biology
Biochemistry

Background:

Intercellular auxin transport is essential for plant development.
Pin-formed (PIN) proteins and phosphoglycoprotein (PGP) transporters are known to be involved in auxin transport.
The precise molecular function of PIN proteins in auxin transport remains unclear.

Purpose of the Study:

To elucidate the molecular mechanism of PIN protein function in auxin transport.
To determine if PIN proteins can mediate auxin efflux independently of other plant-specific factors.

Main Methods:

Utilized mammalian and yeast cell systems to test PIN protein function.
Employed conditional gain-of-function alleles in Arabidopsis and tobacco cultured cells.
Conducted quantitative measurements of auxin accumulation.

Main Results:

PIN proteins facilitate auxin efflux from both mammalian and yeast cells without requiring additional plant factors.
PIN-mediated auxin efflux is distinct from PGP transporter activity.
PIN activity is rate-limiting, specific to auxins, and sensitive to auxin transport inhibitors.

Conclusions:

PIN proteins directly catalyze cellular auxin efflux.
This finding clarifies the fundamental role of PINs in auxin transport and plant development.