Vav2 catalysis-dependent pathways contribute to skeletal muscle growth and metabolic homeostasis

Skeletal muscle promotes metabolic balance by regulating glucose uptake and the stimulation of multiple interorgan crosstalk. We show here that the catalytic activity of Vav2, a Rho GTPase activator, modulates the signaling output of the IGF1- and insulin-stimulated phosphatidylinositol 3-kinase pathway in that tissue. Consistent with this, mice bearing a Vav2 protein with decreased catalytic activity exhibit reduced muscle mass, lack of proper insulin responsiveness and, at much later times, a metabolic syndrome-like condition. Conversely, mice expressing a catalytically hyperactive Vav2 develop muscle hypertrophy and increased insulin responsiveness. Of note, while hypoactive Vav2 predisposes to, hyperactive Vav2 protects against high fat diet-induced metabolic imbalance. These data unveil a regulatory layer affecting the signaling output of insulin family factors in muscle.


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All studies must disclose on these points even when the disclosure is negative. No statistical methods were used to determine sample size. In general, at least three independent replicates were performed in all experiments. For experiments subjected to higher variability, such as metabolic analyses, a larger number of animals was used. When possible, we have aimed for the replication of the animal experiments in at least two different cohorts. The sample size used for each experiment is indicated at the corresponding figure legend in the manuscript.
Only significant outliers were excluded from the analysis. In figure 7c, one Vav2 L33A/L332A animal was excluded (0 min time-point). In figure S16c, one CD-fed WT was excluded in the 0 min time-point. In figure 7k, the 120 min time-point of a WT animal was excluded (lower than the 90 min time-point for the same mouse and significantly lower than the other animals). In figure 1a, one WT mice was excluded due to its low lean mass and abnormal metabolic parameters. In figure S11c, a 2-month-old Vav2 L332A/L332A animal was excluded due to its high adiposity content. In Fig. 8A, a WT animal had to be excluded from the final analysis and sacrificed due to health problems.
The number of independent replicates for each experiment is indicated at the corresponding figure legend in the manuscript. In general, at least three independent replicates were performed.
In all cell and animal studies, groups were allocated randomly. Age and gender-matched animals were used in all the experiments.
For all animal studies, the investigators were blind to group allocation. Blinding was not applicable to the rest of experiments. Commercially available antibodies (see above) have been validated by the manufacturer for the application (immunoblot, immunoprecipitation or immnunocytochemistry) and species. This information is available at each manufacturer's website and can be obtained through the catalog numbers indicated above. The homemade Vav2 antibody has been validated by us in overexpression, knockdown and knockout experiments.