TMEM135 and very long chain acyl-CoA dehydrogenase deficiency: Based on our findings that TMEM135 is highly expressed in VLCAD mice at birth (when lipid stores are strongly mobilized), and given a potential role for TMEM135 in fatty acid oxidation, we hypothesized that TMEM135 protein levels would be upregulated upon physiological stresses such as cold exposure and fasting (conditions in which fat stores and fat utilization are required).