Increased Expression of the Tail-Anchored Membrane Protein SLMAP in Adipose Tissue from Type 2 Tally Ho Diabetic Mice

The tail-anchored membrane protein, sarcolemmal membrane associated protein (SLMAP) is encoded to a single gene that maps to the chromosome 3p14 region and has also been reported in certain diabetic populations. Our previous studies with db/db mice shown that a deregulation of SLMAP expression plays an important role in type 2 diabetes. Male Tally Ho mice were bred to present with either normoglycemia (NG) or hyperglycemia (HG). Abdominal adipose tissue from male Tally Ho mice of the HG group was found to have a significantly lower expression of the membrane associated glucose transporter-4 (GLUT-4) and higher expression of SLMAP compared to tissue from NG mice. There were 3 isoforms expressed in the abdominal adipose tissue, but only 45 kDa isoform of SLMAP was associated with the GLUT-4 revealed by immunoprecipitation data. Knock down studies using SLMAP siRNA with adipocytes resulted in a significant reduction in SLMAP and a decrease in glucose uptake. Thus, SLMAP may be an important regulator of glucose uptake or involved in GLUT-4 fusion/translocation into the plasma membrane of mouse abdominal adipose tissue and changes in SLMAP expression are linked to hyperglycemia and diabetes

Stability and chaos of the duopoly model of Kopel: A study based on symbolic computations

Since Kopel's duopoly model was proposed about three decades ago, there are almost no analytical results on the equilibria and their stability in the asymmetric case. The first objective of our study is to fill this gap. This paper analyzes the asymmetric duopoly model of Kopel analytically by using several tools based on symbolic computations. We discuss the possibility of the existence of multiple positive equilibria and establish necessary and sufficient conditions for a given number of positive equilibria to exist. The possible positions of the equilibria in Kopel's model are also explored. Furthermore, if the duopolists adopt the best response reactions or homogeneous adaptive expectations, we establish rigorous conditions for the existence of distinct numbers of positive equilibria for the first time. The occurrence of chaos in Kopel's model seems to be supported by observations through numerical simulations, which, however, is challenging to prove rigorously. The second objective is to prove the existence of snapback repellers in Kopel's map, which implies the existence of chaos in the sense of Li-Yorke according to Marotto's theorem.Comment: arXiv admin note: substantial text overlap with arXiv:2301.1262