posted on 2019-11-01, 18:39authored byBrooke
L. Brauer, Thomas M. Moon, Sarah R. Sheftic, Isha Nasa, Rebecca Page, Wolfgang Peti, Arminja N. Kettenbach
The
Phosphoprotein Phosphatase Calcineurin (CN, PP2B, PP3) recognizes
and binds to two short linear motifs (SLiMs), PxIxIT and LxVP, in
its regulators and substrates. These interactions enable CN function
in many key biological processes. The identification of SLiMs is difficult
because of their short, degenerate sequence and often low binding
affinity. Here we combine Structure Based Shape Complementarity (SBSC) analysis and proteome-wide affinity purification-mass
spectrometry to identify PxIxIT and LxVP containing CN interactors
to expand and thereby redefine the LxVP motif. We find that the new
πφ-LxVx primary sequence defines an ensemble of binding
competent confirmations and thus the binding on-rate, making it difficult
to predict the LxVP binding strength from its sequence. Our analysis
confirms existing and, more importantly, identifies novel CN interactors,
substrates, and thus biological functions of CN.