Correction of error and new information on P58IPK/DnajC3.
We wish to correct an error in figure 6D and to alert the readers to an important new finding pertaining to our paper: Oyadomari S, Yun C, Fisher EA, Kreglinger N, Kreibich G, Oyadomari M, Harding HP, Goodman AG, Harrant H, Garrision JL, Taunton J, Katze MG and Ron D. 2006. Co-Translocational degradation protects the stressed endoplasmic reticulum from protein overload. Cell. 126:727-739.
The top right panel with the photomicrograph of the P58IPK-/-;Ins2+/+ pancreas in figure 6D was inadvertently duplicated, replacing the image of the P58IPK+/-;Ins2+/+ pancreas. The correct image is presented below. We thank Paul Anderson of Harvard Medical School for first calling our attention to this error.
NEW UNPUBLISHED INFORMATION
In experiments conducted after publication of the paper we have discovered that the N-terminal 26 amino acids of P58IPK are required for complex formation with stalled VCAM-1 in vivo. Further scrutiny of this region suggested that it might function as a signal peptide, directing translocation of P58IPK into the ER lumen. While P58IPK is clearly associated with the ER, its distribution between the cytoplasmic and exofacial side of the membrane has not yet been established experimentally. We have, however, established that fusion of P58IPK containing the 26 N-terminal amino acids can direct the translocation of a heterologous protein into the ER lumen, whereas P58IPK lacking this portion fails to do so. This new finding was unanticipated by the literature, which had placed P58IPK in contact with cytosolic proteins and therefore facing the cytoplasmic side of the ER. Nonetheless, it suggests the need to consider alternatives to the model proposed in Figure 7B to explain P58IPK’s role in the degradation of stalled translocating proteins.
David Ron & Seiichi Oyadomari
NYU School of Medicine
October 20, 2006