Challenge to reveal the ER targeting suppressor

2015 Fiscal Year Final Research Report

• Project/Area Number: 26650063
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Cell biology
• Research Institution: University of Hyogo
• Principal Investigator: Sakaguchi Masao 兵庫県立大学, 生命理学研究科, 教授 (30205736)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: 小胞体 / 膜タンパク質 / ペルオキシソーム / シグナル配列

Outline of Final Research Achievements

Many membrane proteins possessing hydrophobic transmembrane segments are cotranslationally integrated into the ER membrane. Various peroxisomal and mitochondrial membrane proteins escape the ER-targeting mechanism and are targeted to their destinations. Here we discovered a short segment in the 70-kDa peroxisomal membrane protein (PMP70) that suppresses ER targeting. The first transmembrane segment has an intrinsic signal function. The ER-targeting was suppressed by a short N-terminal sequence of 9 residues that is 80 residues upstream of the transmembrane segment. Among the 9 residues, Ser5 is indispensable. The short segment also suppressed the signal peptide function of an authentic secretory protein. The 50-kDa and 20-kDa proteins were crosslinked with the motif. We propose the concept of an ER-targeting suppressor that suppresses the ER-targeting mechanism via a binding factor.

Free Research Field

分子細胞生物学