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TBC1D4
AS160 (Akt substrate of 160 kDa), which was originally known as TBC1 domain family member 4 (TBC1D4), is a Rab GTPase-activating protein that in humans is encoded by the ''TBC1D4'' gene. The 160 kD protein product was first discovered in a screen for novel substrates of the serine-threonine kinase Akt2, which phosphorylates AS160 at Thr-642 and Ser-588 after insulin stimulation. Insulin stimulation of fat and muscle cells results in translocation of the glucose transporter GLUT4 to the plasma membrane, and this translocation process is dependent on phosphorylation of AS160. The role of AS160 in GLUT4 translocation is mediated by its GTPase activating domain and interactions with Rab proteins in vesicle formation, increasing GLUT4 translocation when its GTPase activity is inhibited by Akt phosphorylation. Specifically, this inhibition activates RAB2A, RAB8A Ras-related protein Rab-8A is a protein that in humans is encoded by the ''RAB8A'' gene. Function The protein encoded ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GLUT4
Glucose transporter type 4 (GLUT4), also known as solute carrier family 2, facilitated glucose transporter member 4, is a protein encoded, in humans, by the ''SLC2A4'' gene. GLUT4 is the insulin-regulated glucose transporter found primarily in adipose tissues and striated muscle (skeletal and cardiac). The first evidence for this distinct glucose transport protein was provided by David James in 1988. The gene that encodes GLUT4 was cloned and mapped in 1989. At the cell surface, GLUT4 permits the facilitated diffusion of circulating glucose down its concentration gradient into muscle and fat cells. Once within cells, glucose is rapidly phosphorylated by glucokinase in the liver and hexokinase in other tissues to form glucose-6-phosphate, which then enters glycolysis or is polymerized into glycogen. Glucose-6-phosphate cannot diffuse back out of cells, which also serves to maintain the concentration gradient for glucose to passively enter cells. Structure Like all proteins, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
