Disruption of Fyn SH3 domain interaction with a proline-rich motif in liver kinase B1 results in activation of AMP-activated protein kinase
Authors: Eijiro Yamada
Claire C Bastie
Journal: PLoS ONE (2014)
Discipline: Multidisciplinary
Keywords: Fyn; AMP-activated Protein Kinase (AMPK); Liver Kinase B1 (LKB1); skeletal muscle; tyrosine sites
Affiliations: Diabetes Research and Training Center, Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, United States of America ; Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, United States of America ; Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Gunma, Japan., Diabetes Research and Training Center, Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, United States of America ; Division Metabolic and Vascular Health, Warwick Medical School, University of Warwick, Coventry, United Kingdom.

Abstract:  Fyn-deficient mice display increased AMP-activated Protein Kinase (AMPK) activity as a result of Fyn-dependent regulation of Liver Kinase B1 (LKB1) in skeletal muscle. Mutation of Fyn-specific tyrosine sites in LKB1 results in LKB1 export into the cytoplasm and increased AMPK activation site phosphorylation. This study characterizes the structural elements responsible for the physical interaction between Fyn and LKB1. Effects of point mutations in the Fyn SH2/SH3 domains and in the LKB1 proline-rich motif on 1) Fyn and LKB1 binding, 2) LKB1 subcellular localization and 3) AMPK phosphorylation were investigated in C2C12 muscle cells. Additionally, novel LKB1 proline-rich motif mimicking cell permeable peptides were generated to disrupt Fyn/LKB1 binding and investigate the consequences on AMPK activity in both C2C12 cells and mouse skeletal muscle. Mutation of either Fyn SH3 domain or the proline-rich motif of LKB1 resulted in the disruption of Fyn/LKB1 binding, re-localization of 70% of LKB1 signal in the cytoplasm and a 2-fold increase in AMPK phosphorylation. In vivo disruption of the Fyn/LKB1 interaction using LKB1 proline-rich motif mimicking cell permeable peptides recapitulated Fyn pharmacological inhibition. We have pinpointed the structural elements within Fyn and LKB1 that are responsible for their binding, demonstrating the functionality of this interaction in regulating AMPK activity. 

Retracted: No

PubPeer comments:
 #1 it is hundred participants, all the rest are typos. Editor did not want to change anything because Dr Raouafi (my supervisor) and me refuses to pay APC they asked (when they contact my supervisor it was supposed to be free) , 
 This paper has some inconsistencies in the number of study participants. Hopefully, the authors can provide some clarity. * The Abstract states:  We recruited **one hundred** participants through universities in Montreal, Canada. * Methods:  We recruited **one hundred** participants through universities in Montreal, Canada.  * Methods:  **Hundred** respondents were assessed in subjective cognitive difficulties * Results:  We analysed **60** subjects out of 368 sampled individuals that responded to our questionnaire in this study.  * Table 1 - Sociodemographic 1-4 numbers add up to **100**. * Table 1 - Continent 1-6 numbers add up to **130**. Could the authors please clarify how many subjects were included in this study? , 
 Looking at Table 1, more questions arise. * What do the three columns on the right show? Based on the descriptions in the text, I have assumed that column 2 shows the total numbers, while columns 3 and 4 refer to men and women, respectively. * What do numbers 1-4 refer to in the top of the table? Are these age groups? * In the top rows, why are the percentages behind the (assumed) total numbers not as expected? For example, a number is listed as 51(54.4) or  20 (27.5) . With a total of 100 participants, the numbers seems off. * What do the 6  continents refer to? The text says  We recruited one hundred participants through universities in Montreal, Canada , so it is surprising to see participants from 6 continents. * In particular in the  continent rows, the total numbers add up to 130, not 100 participants, but the percentages suggest there were 100 subjects. It looks as if the row labeled (continent) 6 might have been mislabeled, which seems the most likely assumption. Could the authors explain? * The Sleep Duration 4h row lists a total of 11 persons, ten of those were men. However, no women are listed in this row, so the numbers do not add up to 11. * The Sleep Duration 6-8h row lists a total of 39 subjects, 5 men and 28 women, which would add up to 33. * The Sleep Duration 8h row lists a total of 2 subjects, 4 men and 5 women, which would add up to 9. * In the Cognitive parameters, the scores listed in the (assumed) total column are expected to be the mean of the men and women values, since the gender ratio is 50:50. Could the authors explain why these values are very different? ![file] ,