Proteogenomic Analysis Identifies a Novel Human SHANK3 Isoform.

Fahad Benthani,Phuong Tran,Louise Carey,Laurent Pangon,Maija Kohonen-Corish,Irvin Ng,Marc Giry-Laterriere,Nicola Currey

doi:10.3390/ijms160511522

Abstract

Mutations of the SHANK3 gene have been associated with autism spectrum disorder. Individuals harboring different SHANK3 mutations display considerable heterogeneity in their cognitive impairment, likely due to the high SHANK3 transcriptional diversity. In this study, we report a novel interaction between the Mutated in colorectal cancer (MCC) protein and a newly identified SHANK3 protein isoform in human colon cancer cells and mouse brain tissue. Hence, our proteogenomic analysis identifies a new human long isoform of the key synaptic protein SHANK3 that was not predicted by the human reference genome. Taken together, our findings describe a potential new role for MCC in neurons, a new human SHANK3 long isoform and, importantly, highlight the use of proteomic data towards the re-annotation of GC-rich genomic regions.

Highlights

SHANK3 has been described as one of the most promising candidate susceptibility genes for autism and autism spectrum disorders [1,2,3]
We recently reported that Mutated in colorectal cancer (MCC) is enriched at the migratory edge of colon epithelial cells and binds to the PDZ-domain containing protein SCRIB [19]
In order to identify novel MCC interacting partners we undertook a series of co-immunoprecipitation assays using endogenous MCC as bait, followed by mass spectrometric analyses

Summary

Introduction

SHANK3 has been described as one of the most promising candidate susceptibility genes for autism and autism spectrum disorders [1,2,3]. SHANK3 is a large protein with a well defined PDZ-domain that binds several effector proteins such as βPIX, receptor tyrosine kinase RET9, latrophilin, L-type Ca2+ channels CaV1.3a C, mGluR and GKAP [6,7,8,9,10,11,12,13,14]. Despite its high expression level in the brain [24] no functional study in the neural tissue has been performed. A recent study identified MCC as a potential candidate gene for autism spectrum disorders [25]. We used a proteogenomic approach to identify a novel SHANK3 isoform that binds to MCC

Results

Discussion

Experimental Section

Co-Immunoprecipitation and Western Blotting

Immunofluorescence Microscopy