GLUT4 Recycles via a<i>trans</i>-Golgi Network (TGN) Subdomain Enriched in Syntaxins 6 and 16 But Not TGN38: Involvement of an Acidic Targeting Motif

Shewan, Annette M.; Dam, Ellen M. van; Martin, Sally; Luen, Tang Bor; Hong, Wanjin; Bryant, Nia J.; James, David E.

doi:10.1091/mbc.e02-06-0315

Cited by 194 publications

(262 citation statements)

References 56 publications

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Section: Characterization Of P115 Localization and Function By Immunosupporting

confidence: 83%

“…To further determine the relationship of GLUT4 and p115, we compared the localization of the latter to the Golgi proteins, syntaxin6 and GM130, as shown in Figure 5B. These three proteins overlap to a much greater extent than do p115 and Glut4, consistent with previous data (Shewan et al, 2003).To determine if this p115-GSV colocalization has functional significance, we used electroporation to overexpress the N-and C-terminal p115 constructs described in Figure 4 that we fused to EGFP for reporting their presence by immunofluorescence. We show that the electroporation procedure itself, using EGFP expression alone, does not affect endogenous GLUT4 trafficking (Figure 6, A and B).…”

supporting

confidence: 84%

“…As additional support for a possible functional role for p115 localization at the plasma membrane, we recently detected this protein in detergent-resistant PM lipid rafts isolated from insulin-treated adipocytes (unpublished data). We did not observe a significant signal for p115 in Western blots of immunoadsorbed GLUT4 vesicles (not shown).A possible site of p115 function relevant to GSV trafficking is the trans-Golgi apparatus, which has been suggested to play a part in the trafficking of GSVs/GLUT4 based, in part, on colocalization of GLUT4 with the trans-Golgi marker, syntaxin6 (Shewan et al, 2003). However, whereas the expression of the p115-N-terminus disperses the GLUT4 signal throughout the cytosol and blocks its translocation, this construct is without effect on GM130 distribution ( Figure 6E).…”

mentioning

confidence: 77%

“…A possible site of p115 function relevant to GSV trafficking is the trans-Golgi apparatus, which has been suggested to play a part in the trafficking of GSVs/GLUT4 based, in part, on colocalization of GLUT4 with the trans-Golgi marker, syntaxin6 (Shewan et al, 2003). However, whereas the expression of the p115-N-terminus disperses the GLUT4 signal throughout the cytosol and blocks its translocation, this construct is without effect on GM130 distribution ( Figure 6E).…”

Section: Discussionmentioning

confidence: 98%

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p115 Interacts with the GLUT4 Vesicle Protein, IRAP, and Plays a Critical Role in Insulin-stimulated GLUT4 Translocation

Hosaka

Brooks

Presman

et al. 2005

MBoC

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Insulin-regulated aminopeptidase (IRAP) is an abundant cargo protein of Glut4 storage vesicles (GSVs) that traffics to and from the plasma membrane in response to insulin. We used the amino terminus cytoplasmic domain of IRAP, residues 1-109, as an affinity reagent to identify cytosolic proteins that might be involved in GSV trafficking. In this way, we identified p115, a peripheral membrane protein known to be involved in membrane trafficking. In murine adipocytes, we determined that p115 was localized to the perinuclear region by immunofluorescence and throughout the cell by fractionation. By immunofluorescence, p115 partially colocalizes with GLUT4 and IRAP in the perinuclear region of cultured fat cells. The amino terminus of p115 binds to IRAP and overexpression of a N-terminal construct results in its colocalization with GLUT4 throughout the cell. Insulin-stimulated GLUT4 translocation is completely inhibited under these conditions. Overexpression of p115 C-terminus has no significant effect on GLUT4 distribution and translocation. Finally, expression of the p115 N-terminus construct has no effect on the distribution and trafficking of GLUT1. These data suggest that p115 has an important and specific role in insulin-stimulated Glut4 translocation, probably by way of tethering insulin-sensitive Glut4 vesicles at an as yet unknown intracellular site. INTRODUCTIONInsulin normalizes blood glucose levels by mobilizing the muscle and adipocyte glucose transporter isoform, GLUT4, from intracellular storage vesicles and moving it to the plasma membrane (Simpson et al., 2001;Bryant et al., 2002). Various models of GLUT4 trafficking suggest that GLUT4 must exist in more than one intracellular compartment and the major insulin sensitive pool is localized to a compartment that is distinct from endosomal markers and is commonly referred to as glucose transporter storage vesicles (GSVs), or insulin responsive vesicle (IRVs). Despite the critical function of glucose transport in glucose homeostasis, many of the details by which adipocytes and muscle form a pathway of insulin-sensitive GLUT4 trafficking remain unknown. However, it is virtually certain that the major cargo proteins of GSVs must interact with a number of cytosolic and membrane proteins, such as adaptors and tethers, in order to be properly sorted and regulated by insulin.Insulin-responsive aminopeptidase (IRAP) was identified as an abundant cargo protein associated with GLUT4 vesicles that translocates in response to insulin in a manner seemingly identical to GLUT4 Mastick et al., 1994;Keller et al., 1995;Malide et al., 1997;Martin et al., 1997;Ross et al., 1997). In fact, it is more abundantly expressed in vesicles than the transporter (Kupriyanova et al., 2002). When the cytoplasmic N-terminus of IRAP was microinjected into 3T3-L1 adipocytes, GLUT4 was localized on the plasma membrane even in the basal state (Waters et al., 1997), suggesting IRAP can play a role in GSV movement/targeting. A chimeric protein containing the intracellular domain of IRAP and ...

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Section: Characterization Of P115 Localization and Function By Immunosupporting

confidence: 83%

supporting

confidence: 84%

mentioning

confidence: 77%

Section: Discussionmentioning

confidence: 98%

See 2 more Smart Citations

p115 Interacts with the GLUT4 Vesicle Protein, IRAP, and Plays a Critical Role in Insulin-stimulated GLUT4 Translocation

Hosaka

Brooks

Presman

et al. 2005

MBoC

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“…Subsequently GLUT4 becomes sequestered from these compartments and equilibrates with the remaining GLUT4 protein in the IRC [38]. It has also been suggested that GLUT4 may not necessary directly traffic back to the IRC but may re-enter into the Golgi/TGN secretory system and then undergo sorting to the IRC [102]. Although the sorting proteins involved in these processes have only been poorly defined, the adaptor protein 2 (AP2) complex is required for the plasma membrane sorting into clathrin-coated pits [103,104].…”

Section: Glut4 Endocytosismentioning

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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Isolation of GLUT4 Storage Vesicles

Kandror

Pilch

2006

CP Cell Biology

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The immunoisolation of GLUT4‐containing vesicles from adipocytes is described in this unit. The methods involve homogenization of cells followed by differential centrifugation to provide the intracellular membranes that contain GLUT4. Subsequently, an immobilized monoclonal antibody is used for the isolation of vesicles of very high purity. The various protocols are applicable to cultured and primary adipocytes as well as skeletal muscle, the major insulin target cells expressing GLUT4.

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GLUT4 Recycles via atrans-Golgi Network (TGN) Subdomain Enriched in Syntaxins 6 and 16 But Not TGN38: Involvement of an Acidic Targeting Motif

Cited by 194 publications

References 56 publications

p115 Interacts with the GLUT4 Vesicle Protein, IRAP, and Plays a Critical Role in Insulin-stimulated GLUT4 Translocation

p115 Interacts with the GLUT4 Vesicle Protein, IRAP, and Plays a Critical Role in Insulin-stimulated GLUT4 Translocation

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

Isolation of GLUT4 Storage Vesicles

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