Interaction of the Akt Substrate, AS160, with the Glucose Transporter 4 Vesicle Marker Protein, Insulin-Regulated Aminopeptidase

Peck, Grantley R.; Ye, Siying; Pham, Vi; Fernando, Ruani; Macaulay, S. Lance; Chai, Siew Yeen; Albiston, Anthony L.

doi:10.1210/me.2005-0476

Cited by 79 publications

(79 citation statements)

References 47 publications

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“…The Rab Gap, AS160, plays an important role in insulin-dependent GLUT4 trafficking (50), and it has been shown to bind to IRAP in pulldown (51) and vesicle adsorption experiments (52). The intracellular sequence of LRP1 has homologies to that of IRAP, and accordingly, we performed pulldown experiments with cytosolic sequences from IRAP, sortilin, and LRP1, and we blotted for AS160 as show in Fig.…”

Section: Lrp1 C Terminus Binds Akt Substrate Of 160 Kda (As160)-mentioning

confidence: 99%

Proteomic Analysis of GLUT4 Storage Vesicles Reveals LRP1 to Be an Important Vesicle Component and Target of Insulin Signaling

Jedrychowski

Gartner

Gygi

et al. 2010

Journal of Biological Chemistry

114

146

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Insulin stimulates the translocation of intracellular GLUT4 to the plasma membrane where it functions in adipose and muscle tissue to clear glucose from circulation. The pathway and regulation of GLUT4 trafficking are complicated and incompletely understood and are likely to be contingent upon the various proteins other than GLUT4 that comprise and interact with GLUT4-containing vesicles. Moreover, not all GLUT4 intracellular pools are insulin-responsive as some represent precursor compartments, thus posing a biochemical challenge to the purification and characterization of their content. To address these issues, we immunodepleted precursor GLUT4-rich vesicles and then immunopurified GLUT4 storage vesicle (GSVs) from primary rat adipocytes and subjected them to semi-quantitative and quantitative proteomic analysis. The purified vesicles translocate to the cell surface almost completely in response to insulin, the expected behavior for bona fide GSVs. In total, over 100 proteins were identified, about 50 of which are novel in this experimental context. LRP1 (low density lipoprotein receptorrelated protein 1) was identified as a major constituent of GSVs, and we show it interacts with the lumenal domains of GLUT4 and other GSV constituents. Its cytoplasmic tail interacts with the insulin-signaling pathway target, AS160 (Akt substrate of 160 kDa). Depletion of LRP1 from 3T3-L1 adipocytes reduces GLUT4 expression and correspondingly results in decreased insulin-stimulated 2-[ 3 H]deoxyglucose uptake. Furthermore, adipose-specific LRP1 knock-out mice also exhibit decreased GLUT4 expression. These findings suggest LRP1 is an important component of GSVs, and its expression is needed for the formation of fully functional GSVs.The insulin-dependent translocation of GLUT4 from intracellular membranes to the cell surface is a well studied paradigm for the effects of signal transduction on membrane trafficking, and this process is of considerable physiological relevance for the regulation of glucose homeostasis, as dysregulation of this process plays a role in insulin resistance and type 2 diabetes mellitus (1). Only about half of the intracellular GLUT4 translocates to the plasma membrane in response to insulin (2-5) suggesting that more than one GLUT4-containing compartment exists. In addition, kinetic analyses of GLUT4 trafficking are consistent with the interpretation that GLUT4 traffics through multiple intracellular compartments (6 -8). These and other data have led to the concept that an ultimate target of insulin signaling is a subpopulation of translocating GLUT4-containing membranes that are commonly referred to as GLUT4 storage vesicles (GSVs) 3 (9, 10). The focus of many groups over the years has been on how these GSVs form, what their protein composition is, and how insulin communicates with them and stimulates their translocation to the cell surface.GLUT4-containing vesicles have been purified and their protein composition analyzed by a number of investigators, first by conventional protein sequencing (11, 12)...

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Section: Lrp1 C Terminus Binds Akt Substrate Of 160 Kda (As160)-mentioning

confidence: 99%

Proteomic Analysis of GLUT4 Storage Vesicles Reveals LRP1 to Be an Important Vesicle Component and Target of Insulin Signaling

Jedrychowski

Gartner

Gygi

et al. 2010

Journal of Biological Chemistry

114

146

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“…The active Rab would then promote vesicle trafficking in an as of yet undefined manner. Alternatively, it has also been proposed that AS160 directly associates with another IRC cargo protein IRAP, and that insulin-dependent Akt phosphorylation results in the dissociation of AS160 from GLUT4 compartment and would also lead to Rab activation [80]. Although these studies have suggested that AS160 serves as the insulin-regulated ratelimiting step in GLUT4 translocation, both an in vitro plasma membrane reconstitution fusion system and in vivo TIRF microscopy measurements indicate that the critical site of insulin regulation is the plasma membrane fusion process downstream of AS160 [23,25].…”

Section: Insulin Signaling Leading To Glut4 Translocationmentioning

confidence: 99%

Ins (endocytosis) and outs (exocytosis) of GLUT4 trafficking

Hou

Pessin

2007

Current Opinion in Cell Biology

132

116

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SummaryGlucose transporter 4 (GLUT4) is the major insulin regulated glucose transporter expressed mainly in muscle and adipose tissue. GLUT4 is stored in a poorly characterized intracellular vesicular compartment and translocates to the cell surface in response to insulin stimulation resulting in increase glucose uptake. This process is essential for the maintenance of normal glucose homeostasis and involves a complex interplay of trafficking events and intracellular signaling cascades. Recent studies have identified sortilin as an essential element for the formation of GLUT4 storage vesicles during adipogenesis and GGA (Golgi-localized γ-ear-containing Arf-binding protein) as a key coat adaptor for the entry of newly synthesized GLUT4 into the specialized compartment. Insulinstimulated GLUT4 translocation from this compartment to the plasma membrane appears to require the Akt/protein kinase B substrate, termed AS160 (Akt Substrate of 160 kDa). In addition, the VPS9 domain-containing protein Gapex-5 in complex with CIP4 appears to function as a Rab31 guanylnucleotide exchange factor that is necessary for insulin-stimulated GLUT4 translocation. Here we attempt to summaries recent advances in GLUT4 vesicle biogenesis, intracellular trafficking and membrane fusion.

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“…Besides the RabGAP domain at the C terminus, AS160 also has two phosphotyrosine binding domains (PTBs) at the N terminus and a calmodulin binding domain in the middle. The PTBs of AS160 can bind phospholipids (20) as well as the insulin-regulated aminopeptidase (IRAP) that associates with GSVs (21). An N-terminal AS160 fragment was detected in transformed lymphocytes from a human patient bearing the AS160 Arg363Ter mutation (18).…”

mentioning

confidence: 99%

The Inactivation of RabGAP Function of AS160 Promotes Lysosomal Degradation of GLUT4 and Causes Postprandial Hyperglycemia and Hyperinsulinemia

Xie

Chen

et al. 2016

Diabetes

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The AS160 (Akt substrate of 160 kDa) is a Rab-GTPase activating protein (RabGAP) with several other functional domains, and its deficiency in mice or human patients lowers GLUT4 protein levels and causes severe insulin resistance. How its deficiency causes diminished GLUT4 proteins remains unknown. We found that the deletion of AS160 decreased GLUT4 levels in a cell/ tissue-autonomous manner. Consequently, skeletal muscle-specific deletion of AS160 caused postprandial hyperglycemia and hyperinsulinemia. The pathogenic effects of AS160 deletion are mainly, if not exclusively, due to the loss of its RabGAP function since the RabGAP-inactive AS160 R917K mutant mice phenocopied the AS160 knockout mice. The inactivation of RabGAP of AS160 promotes lysosomal degradation of GLUT4, and the inhibition of lysosome function could restore GLUT4 protein levels. Collectively, these findings demonstrate that the RabGAP activity of AS160 maintains GLUT4 protein levels in a cell/tissue-autonomous manner and its inactivation causes lysosomal degradation of GLUT4 and postprandial hyperglycemia and hyperinsulinemia.

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Interaction of the Akt Substrate, AS160, with the Glucose Transporter 4 Vesicle Marker Protein, Insulin-Regulated Aminopeptidase

Cited by 79 publications

References 47 publications

Proteomic Analysis of GLUT4 Storage Vesicles Reveals LRP1 to Be an Important Vesicle Component and Target of Insulin Signaling

Proteomic Analysis of GLUT4 Storage Vesicles Reveals LRP1 to Be an Important Vesicle Component and Target of Insulin Signaling

Ins (endocytosis) and outs (exocytosis) of GLUT4 trafficking

The Inactivation of RabGAP Function of AS160 Promotes Lysosomal Degradation of GLUT4 and Causes Postprandial Hyperglycemia and Hyperinsulinemia

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