Biophysical assay for tethered signaling reactions reveals tether-controlled activity for the phosphatase SHP-1

Journal article

Tethered enzymatic reactions are ubiquitous in signalling networks but are poorly understood. Here, a novel mathematical analysis is established for tethered signalling reactions in surface plasmon resonance (SPR). Applying the method to the phosphatase SHP-1 interacting with a phosphorylated tether corresponding to an immune receptor cytoplasmic tail provides 5 biophysical/biochemical constants from a single SPR experiment: two binding rates, two catalytic rates, and a reach parameter. Tether binding increased the activity of SHP-1 by 900-fold through a binding-induced allosteric activation (20-fold) and a more significant increase in local substrate concentration (45-fold). The reach parameter indicates that this local substrate concentration is exquisitely sensitive to receptor clustering. We further show that truncation of the tether leads not only to a lower reach but also to lower binding and catalysis. The work establishes a new framework for studying tethered signalling processes and highlights the tether as a control parameter in clustered receptor signalling.

Authors: Goyette, J; Solis Salas, C; Coker-Gordon, N; Bridge, M; Isaacson, S

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Association for the Advancement of Science: Science Advances
• Journal: Science Advances
• Volume: 3
• Issue: 3
• Article number: e1601692
• Publication date: 2017-01-01
• Acceptance date: 2017-02-09
• DOI: 10.1126/sciadv.1601692
• ISSN: 2375-2548