Sorting of Œ≤1-adrenergic receptors is mediated by pathways that are either dependent on or independent of type I PDZ, protein kinase A (PKA), and SAP97
Authors: Suleiman W Bahouth
Maryanne M Chumpia
Mohammed M Nooh
Thomas B Hamilton
Journal: Journal of Biological Chemistry (2014)
Discipline: BIOLOGY & BIOCHEMISTRY
Keywords: Adrenergic Receptor; Confocal Microscopy; G Protein-coupled Receptor (GPCR); Protein Kinase A (PKA); Trafficking.
Affiliations: From the Department of Pharmacology, University of Tennessee Health Sciences Center, Memphis, Tennessee 38163 and.

Abstract:  The Œ≤1-adrenergic receptor (Œ≤1-AR) is a target for treatment of major cardiovascular diseases, such as heart failure and hypertension. Recycling of agonist-internalized Œ≤1-AR is dependent on type I PSD-95/DLG/ZO1 (PDZ) in the C-tail of the Œ≤1-AR and on protein kinase A (PKA) activity (Gardner, L. A., Naren, A. P., and Bahouth, S. W. (2007) J. Biol. Chem. 282, 5085-5099). We explored the effects of point mutations in the PDZ and in the activity of PKA on recycling of the Œ≤1-AR and its binding to the PDZ-binding protein SAP97. These studies indicated that Œ≤1-AR recycling was inhibited by PKA inhibitors and by mutations in the PDZ that interfered with SAP97 binding. The trafficking effects of short sequences differing in PDZ and SAP97 binding were examined using chimeric mutant Œ≤1-AR. Œ≤1-AR chimera containing the type I PDZ of the Œ≤2-adrenergic receptor that does not bind to SAP97 failed to recycle except when serine 312 was mutated to aspartic acid. Œ≤1-AR chimera with type I PDZ sequences from the C-tails of aquaporin-2 or GluR1 recycled in a SAP97- and PKA-dependent manner. Non-PDZ Œ≤1-AR chimera derived from Œº-opioid, dopamine 1, or GluR2 receptors promoted rapid recycling of chimeric Œ≤1-AR in a SAP97- and PKA-independent manner. Moreover, the nature of the residue at position -3 in the PDZ regulated whether the Œ≤1-AR was internalized alone or in complex with SAP97. These results indicate that divergent pathways were involved in trafficking the Œ≤1-AR and provide a roadmap for its trafficking via type I PDZs versus non-PDZs. 

Retracted: No

PubPeer comments:
 Blue and green arrows: The cell morphology of different groups appear to look similar in Fig 1A and Fig2A.   , 
 #1 Thank you for your interest in our work. Quality is of paramount importance to us. I will recheck these and all images of this paper on Monday June 21 and get back to you. S Bahouth , 
 #2 Dear commenter Thank you for highlighting what appears to be a duplication in the images W1 and Z. I checked our TIFF images and we have conducted these experiments in triplicate with 15-20 images per experiment. So we have between 45-60 images for each single condition. So I am perplexed why these two were selected when we had so many. I cannot explain, but to apologize for it. It should not have happened period. I believe the problem is with the novicity of summer students who analyze the data by NIH image, where they duplicated the image, but not the data. On the other hand images L and h appear to be similar, but are not duplicates as I was able to find each independent image and personally analyze it for uniqueness. Thank you for alerting us to there errors. Trust me when I tell you that I care very much for accuracy, but my problem (like many scientists in cellular imaging) is the number of images we have to deal with, which with my time limitations, things do slip up as you pointed out. ,