Processing of preproGIP to proGIP Authored: May, B, 2009-05-18 21:31:59 EC Number: 3.4.21 Edited: May, B, 2009-09-09 Pubmed2890159 Reactome Database ID Release 43400496 Reactome, http://www.reactome.org ReactomeREACT_23888 Reviewed: Bloom, SR, 2010-06-24 The GIP mRNA is translated by ribosomes at the outer surface of the rough endoplasmic reticulum. The nascent peptide enters the endoplasmic reticulum through the translocon complex and the signal peptide is cleaved by the signal peptidase.