INS and obesity due to melanocortin 4 receptor deficiency: In our previous studies, we have also found that mice lacking the CDK6 protein or its kinase domain (K43M) exhibited more beige cell formation in the subcutaneous white adipose tissues (SAT) but not in the visceral white adipose tissues (VAT) (Hou et al., 2018), greater energy expenditure (Hou et al., 2018), better glucose tolerance and higher insulin sensitivity (Hou et al., 2018), and were more resistant to high fat diet-induced obesity (Hou et al., 2018).