Insulin resistance phosphatases

The above may be of pathophysiological relevance as a decreased basal and insulin-stimulated glycogen phosphatase activity and phosphorylase phosphatase activity (Type-1 protein phosphatase, PP-1) in the skeletal muscle of insulin-resistant individuals has been found (Freymond era/., 1988 Kida era/., 1990, 1992 Damsbo et al., 1991). Other studies suggest increased phosphotyrosine phosphatase activity in patients with NIDDM who show decreased autoactivation of the insulin receptor kinase (McGuire et al., 1991). 

The low molecular weight acid phosphatase has been implicated in the insulin resistance pathway producing effects that are independent from the high molecular weight protein tyrosine phosphatase (PTPIB) [37, 38]. This renders the low molecular weight protein tyrosine acid phosphatase an interesting target for the treatment of insulin resistance and type 2 diabetes. 

Mouse Fid Phosphatidic acid phosphatase 1 (lipin-1) Impaired adipose development, insulin resistance, increased P-oxidation... 

In detail, adipocytes from visceral adipose tissue are more resistant to insuhn-induced anti-lipolysis and re-esterification of NEFA than those from leg and non-visceral body fat both in vitro [503, 504] and in vivo [505]. Various functional differences in these ceUs have been identified at the level of the insuhn receptor and the post-receptor insulin signahng cascade [503, 504]. PDE3B involved in hpolysis regulation by insuhn (see above. Fig. 11.7) and protein tyrosine phosphatases de-phosphorylating fhe insuhn receptor, such as PTPlb, could be affected in differen-... 

Increased insulin sensitivity and obesity resistance in mice lacking the protein tyrosine phosphatase-IB gene. Science 283 1544-1548... 

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