Cholesterol Interaction with the MAGUK Protein Family Member, MPP1, via CRAC and CRAC-Like Motifs: An In Silico Docking Analysis.

Marcin A Listowski,Sebastian Kraszewski,Jacek Leluk,Aleksander F Sikorski,Robert J Deschenes

doi:10.1371/journal.pone.0133141

Marcin A Listowski, Sebastian Kraszewski + Show 3 more

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https://doi.org/10.1371/journal.pone.0133141

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Abstract

Cholesterol is essential for the proper organization of the biological membrane. Therefore, predicting which proteins can bind cholesterol is important in understanding how proteins participate in lateral membrane organization. In this study, a simple bioinformatics approach was used to establish whether MPP1, a member of the MAGUK protein family, is capable of binding cholesterol. Modelled and experimentally-validated fragment structures were mined from online resources and searched for CRAC and CRAC-like motifs. Several of these motifs were found in the primary structure of MPP1, and these were structurally visualized to see whether they localized to the protein surface. Since all of the CRAC and CRAC-like motifs were found at the surface of MPP1 domains, in silico docking experiments were performed to assess the possibility of interaction between CRAC motifs and cholesterol. The results obtained show that MPP1 can bind cholesterol via CRAC and CRAC-like motifs with moderate to high affinity (KI in the nano- to micro-molar range). It was also found that palmitoylation-mimicking mutations (C/F or C/M) did not affect the affinity of MPP1 towards cholesterol. Data presented here may help to understand at least one of the molecular mechanisms via which MPP1 affects lateral organization of the membrane.

Highlights

A specific sequence motif, termed the cholesterol recognition/interaction amino acid consensus (CRAC) [1], is present in many proteins that are known to interact with cholesterol
The CRAC motif is defined by the pattern–L/V-X1–5-Y-X1–5-R/K
In our analyses, using EMBROSS: fuzzpro, we searched the primary structure of Membrane Palmitoylated Protein 1 (MPP1) for this pattern as well as for its reverse form,R/K-X1–5-Y-X1– 5-L/V–(CARC or CRAC-like motif), along with motifs that possesses a central phenylalanine residue instead of tyrosine (CRAC-like)

Summary

Introduction

A specific sequence motif, termed the cholesterol recognition/interaction amino acid consensus (CRAC) [1], is present in many proteins that are known to interact with cholesterol. It consists of branched apolar amino-acid residues, L and V, followed by any residues in a 1–5 segment, a mandatory aromatic residue Y and, again, a segment of 1–5 of any residues, and ends with K or R. Looseness of the motif definition caused some scepticism about its predictive value [2,3]. This motif is present in many proteins that are known to bind cholesterol and, in many cases, the interaction was confirmed by physicochemical approaches.

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