"We know of over 150 receptors similar to CLV1 in Arabidopsis, but little is known about how they function," Clark says. "Similar structures also are involved in plant disease resistance and human hormone signaling. Understanding how CLV1 and CLV3 work will help scientists understand how the others work, as well."

Like most scientific research, Clark says his discovery raises as many questions as it answers. One big mystery involves unusual two-way communication between the ligand and receptor. "The traditional view is that changes outside the cell membrane caused by ligand binding lead to changes inside the cell, which start the signaling process. For CLV1, it appears that information also flows from inside the cell to the outside. Unless it receives these chemical signals from inside the cell, the receptor will not bind to the ligand."

Then there is the unknown role played by another gene, CLAVATA2. "All we know at the moment is that in plants, CLV2 is required to stabilize CLV1 protein," Clark explains. "Without CLV2, CLV1 protein degrades."

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Contact: Sally Pobojewski
pobo@umich.edu
734-647-1844
University of Michigan
26-Jul-2000