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01.11.2015 | Article

VAV2, a guanine nucleotide exchange factor for Rac1, regulates glucose-stimulated insulin secretion in pancreatic beta cells

verfasst von: Rajakrishnan Veluthakal, Ragadeepthi Tunduguru, Daleep Kumar Arora, Vaibhav Sidarala, Khadija Syeda, Cornelis P. Vlaar, Debbie C. Thurmond, Anjaneyulu Kowluru

Erschienen in: Diabetologia | Ausgabe 11/2015

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Abstract

Aims/hypothesis

Rho GTPases (Ras-related C3 botulinum toxin substrate 1 [Rac1] and cell division cycle 42 [Cdc42]) have been shown to regulate glucose-stimulated insulin secretion (GSIS) via cytoskeletal remodelling, trafficking and fusion of insulin-secretory granules with the plasma membrane. GTP loading of these G proteins, which is facilitated by GDP/GTP exchange factors, is a requisite step in the regulation of downstream effector proteins. Guanine nucleotide exchange factor VAV2 (VAV2), a member of the Dbl family of proteins, has been identified as one of the GDP/GTP exchange factors for Rac1. Despite recent evidence on the regulatory roles of VAV2 in different cell types, roles of this guanine nucleotide exchange factor in the signalling events leading to GSIS remain undefined. Using immunological, short interfering RNA (siRNA), pharmacological and microscopic approaches we investigated the role of VAV2 in GSIS from islet beta cells.

Methods

Co-localisation of Rac1 and VAV2 was determined by Triton X-114 phase partition and confocal microscopy. Glucose-induced actin remodelling was quantified by live cell imaging using the LifeAct-GFP fluorescent biosensor. Rac1 activation was determined by G protein linked immunosorbent assay (G-LISA).

Results

Western blotting indicated that VAV2 is expressed in INS-1 832/13 beta cells, normal rat islets and human islets. Vav2 siRNA markedly attenuated GSIS in INS-1 832/13 cells. Ehop-016, a newly discovered small molecule inhibitor of the VAV2–Rac1 interaction, or siRNA-mediated knockdown of VAV2 markedly attenuated glucose-induced Rac1 activation and GSIS in INS-1 832/13 cells. Pharmacological findings were recapitulated in primary rat islets. A high glucose concentration promoted co-localisation of Rac1 and VAV2. Real-time imaging in live cells indicated a significant inhibition of glucose-induced cortical actin remodelling by Ehop-016.

Conclusions/Interpretation

Our data provide the first evidence to implicate VAV2 in glucose-induced Rac1 activation, actin remodelling and GSIS in pancreatic beta cells.

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Jitrapakdee S, Wutthisathapornchai A, Wallace JC, MacDonald MJ (2010) Regulation of insulin secretion: role of mitochondrial signaling. Diabetologia 53:1019–1032PubMedCentralCrossRefPubMed

Prentki M, Matschinsky FM, Madiraju SR (2013) Metabolic signaling in fuel-induced insulin secretion. Cell Metab 18:162–185CrossRefPubMed

Berggren PO, Leibiger IB (2006) Novel aspects on signal transduction in the pancreatic beta cell. Nutr Metab Cardiovasc Dis 16(suppl 1):S7–S10CrossRefPubMed

Komatsu M, Takei M, Ishii H, Sato Y (2013) Glucose-stimulated insulin secretion: a newer perspective. J Diabetes Investig 4:511–516PubMedCentralCrossRefPubMed

Wang Z, Thurmond DC (2009) Mechanisms of biphasic insulin granule exocytosis-roles of cytoskeleton, small GTPases and SNARE proteins. J Cell Sci 122:893–903PubMedCentralCrossRefPubMed

Kowluru A (2010) Small G proteins in islet β-cell function. Endocr Rev 31:52–78PubMedCentralCrossRefPubMed

Kalwat MA, Thurmond DC (2013) Signaling mechanisms of glucose-induced F-actin remodeling in pancreatic islet β cells. Exp Mol Med 45:1–12CrossRef

Veluthakal R, Kaur H, Goalstone M, Kowluru A (2007) Dominant-negative alpha-subunit of farnesyl-and geranyltransferase inhibits glucose-stimulated, but not KCl-stimulated, insulin secretion in INS 832/13 cells. Diabetes 56:204–210CrossRefPubMed

Wang Z, Oh E, Thurmond DC (2007) Glucose-stimulated Cdc42 signaling is essential for the second phase of insulin secretion. J Biol Chem 282:9536–9546PubMedCentralCrossRefPubMed

10.

Jayaram B, Syed I, Kyathanahalli CN, Rhodes CJ, Kowluru A (2011) Arf nucleotide binding site opener [ARNO] promotes sequential activation of Arf6, cdc42 and Rac1 and insulin secretion in INS 832/13 beta-cells and rat islets. Biochem Pharmacol 81:1016–1027PubMedCentralCrossRefPubMed

11.

Lawrence JT, Birnbaum MJ (2003) ADP-ribosylation factor 6 regulates insulin secretion through plasma membrane phosphatidylinositol 4,5-biphosphate. Proc Natl Acad Sci U S A 100:13320–13325PubMedCentralCrossRefPubMed

12.

Veluthakal R, Madathilperambil SV, McDonald P, Olson LK, Kowluru A (2009) Regulatory roles for Tiam1, a guanine nucleotide exchange factor for Rac1, in glucose-stimulated insulin secretion in pancreatic beta-cells. Biochem Pharmacol 77:101–113PubMedCentralCrossRefPubMed

13.

Kepner EM, Yoder SM, Oh E et al (2011) Cool-1/βPIX functions as a guanine nucleotide exchange factor in the cycling of Cdc42 to regulate insulin secretion. Am J Physiol Endocrinol Metab 301:1072–1080CrossRef

14.

Kowluru A, Veluthakal R (2005) Rho guanosine diphosphate-dissociation inhibitor plays a negative modulatory role in glucose-stimulated insulin secretion. Diabetes 54:3523–3529CrossRefPubMed

15.

Wang Z, Thurmond DC (2010) Differential phosphorylation of RhoGDI mediates the distinct cycling of Cdc42 and Rac1 to regulate second phase insulin secretion. J Biol Chem 285:6186–6197PubMedCentralCrossRefPubMed

16.

Hornstein I, Alcover A, Katzav S (2004) Vav proteins, masters of the world of cytoskeleton organization. Cell Signal 16:1–11CrossRefPubMed

17.

Swat W, Fujikawa K (2005) The Vav family: at the crossroads of signaling. Immunol Res 32:259–265CrossRefPubMed

18.

Cook DR, Rossman KL, Der CJ (2013) Rho guanine nucleotide exchange factors: regulators of Rho GTPase activity in the development and disease. Oncogene 33:4021–4035CrossRefPubMed

19.

Bustelo XR (2000) Regulatory and signaling properties of the Vav family. Mol Cell Biol 20:1461–1477PubMedCentralCrossRefPubMed

20.

Bustelo XR (1996) The VAV family of signal transduction molecules. Crit Rev Oncog 7:65–88CrossRefPubMed

21.

Crespo P, Schuebel KE, Ostrom AA, Gutkind JS, Bustelo XR (1997) Phosphotyrosine-dependent activation of Rac-1 GDP/GTP exchange by the vav proto-oncogene product. Nature 385:169–172CrossRefPubMed

22.

Schuebel KE, Movilla N, Rosa JL, Bustelo XR (1998) Phosphorylation-dependent and constitutive activation of Rho proteins by wild-type and oncogenic Vav-2. EMBO J 17:6608–6621PubMedCentralCrossRefPubMed

23.

Han J, Das B, Wei W et al (1997) Lck regulates Vav activation of members of the Rho family of GTPases. Mol Cell Biol 17:1346–1353PubMedCentralPubMed

24.

Michel F, Grimaud L, Tuosto L, Acuto O (1998) Fyn and ZAP-70 are required for Vav phosphorylation in T cells stimulated by antigen-presenting cells. J Biol Chem 273:31932–31938CrossRefPubMed

25.

Deckert M, Tartare-Deckert S, Couture C, Mustelin T, Altman A (1996) Functional and physical interactions of Syk family kinases with the Vav proto-oncogene product. Immunity 5:591–604CrossRefPubMed

26.

Bustelo XR, Ledbetter JA, Barbacid M (1992) Product of vav proto-oncogene defines a new class of tyrosine protein kinase substrates. Nature 356:68–71CrossRefPubMed

27.

Margolis B, Hu P, Katzav S et al (1992) Tyrosine phosphorylation of vav proto-oncogene product containing SH2 domain and transcription factor motifs. Nature 356:71–74CrossRefPubMed

28.

Yoder SM, Dineen SL, Wang Z, Thurmond DC (2014) YES, a Src family kinase, is a proximal glucose-specific activator of cell division cycle control protein 42 (Cdc42) in pancreatic islet β cells. J Biol Chem 289:11476–11487PubMedCentralCrossRefPubMed

29.

Montalvo-Ortiz BL, Castillo-Pichardo L, Hernandez E, Humphries-Bickley T, De la Mota-Peynado A et al (2012) Characterization of Ehop-016, a novel small molecule inhibitor of Rac GTPase. J Biol Chem 287:13228–13238PubMedCentralCrossRefPubMed

30.

Kowluru RA, Kowluru A, Veluthakal R et al (2014) Tiam1-Rac1 signaling axis-mediated activation of NADPH oxidase-2 initiates mitochondrial damage in the development of diabetic retinopathy. Diabetologia 57:1047–1056CrossRefPubMed

31.

Tunduguru R, Chiu TT, Ramalingam L, Elmendorf JS, Klip A, Thurmond DC (2014) Signaling of the p21-activated kinase (PAK1) coordinates insulin-stimulated actin remodeling and glucose uptake in skeletal muscle cell. Biochem Pharmacol 92:380–388PubMedCentralCrossRefPubMed

32.

del Pozo MA, Kiosses WB, Alderson NB, Meller N, Hahn KM, Schwartz MA (2002) Integrins regulate GTP-Rac localized effector interactions through dissociation of Rho-GDI. Nat Cell Biol 4:232–239CrossRefPubMed

33.

Olofsson B (1999) Rho guanine dissociation inhibitors: pivotal molecules in cellular signalling. Cell Signal 11:545–554CrossRefPubMed

34.

Kalwat MA, Yoder SM, Wang Z, Thurmond DC (2013) A p21-activated kinase (PAK1) signaling cascade coordinately regulates F-actin remodeling and insulin granule exocytosis in pancreatic β cells. Biochem Pharmacol 85:808–816PubMedCentralCrossRefPubMed

35.

Lopez JP, Turner JR, Philipson LH (2010) Glucose-induced ERM protein activation and translocation regulates insulin secretion. Am J Physiol Endocrinol Metab 299:E772–E785PubMedCentralCrossRefPubMed

36.

Kowluru A, Li G, Rabaglia ME, Segu VB, Hofmann F et al (1997) Evidence for differential regulation of Rho subfamily of GTP-binding proteins in glucose-and calcium-induced insulin secretion from pancreatic beta-cells. Biochem Pharmacol 54:1097–1108CrossRefPubMed

37.

Kowluru A, Veluthakal R, Rhodes CJ, Kamath V, Syed I et al (2010) Protein farnesylation-dependent Raf/extracellular signal-related kinase signaling links to cytoskeletal remodeling to facilitate glucose-induced insulin secretion in pancreatic beta-cells. Diabetes 59:967–977PubMedCentralCrossRefPubMed

38.

Kowluru A (2011) Friendly, and not so friendly, roles of Rac1 in islet beta-cell function: lessons learnt from pharmacological and molecular biological approaches. Biochem Pharmacol 81:965–975PubMedCentralCrossRefPubMed

39.

Syed I, Kyathanahalli CN, Kowluru A (2011) Phagocyte-like NADPH oxidase generates ROS in INS 832/13 cells and rat islets: role of protein prenylation. Am J Physiol Regul Integr Comp Physiol 300:756–762CrossRef

40.

Morgan D, Rebelato E, Abdulkader F, Graciano MF, Oliveira-Emilo HR et al (2009) Association of NAD(P)H oxidase with glucose-induced insulin secretion by pancreatic beta-cells. Endocrinology 150:2197–2201CrossRefPubMed

41.

Kowluru A, Kowluru RA (2014) Phagocyte-like NADPH oxidase [Nox2] in cellular dysfunction in models of glucolipotoxicity and diabetes. Biochem Pharmacol 88:275–283CrossRefPubMed

42.

Liu Y, Collins C, Kiosses WB, Murray AM, Joshi M et al (2013) A novel pathway spatiotemporally activates Rac1 and redox signaling in response to fluid shear stress. J Cell Biol 201:863–873PubMedCentralCrossRefPubMed

43.

Servitja JM, Marinissen MJ, Sidhi A, Bustelo XR, Gutkind JS (2003) Rac1 function is required for Src-induced transformation. Evidence of a role for Tiam1 and Vav2 in Rac activation by Src. J Biol Chem 278:34339–34346CrossRefPubMed

44.

Garrett TA, Van Buul JD, Burridge K (2007) VEGF-induced Rac1 activation in endothelial cells is regulated by the guanine nucleotide exchange factor Vav2. Exp Cell Res 313:3285–3297PubMedCentralCrossRefPubMed

45.

Han J, Luby-Phelps K, Das B et al (1998) Role of substrates and products of PI 3-kinase in regulating activation of Rac-related guanosine triphosphatases by Vav. Science 279:558–560CrossRefPubMed

46.

McDonald P, Veluthakal R, Kaur H, Kowluru A (2007) Biologically active lipids promote trafficking and membrane association of Rac1 in insulin-secreting INS 832/13 cells. Am J Physiol Cell Physiol 292:C1216–C1220CrossRefPubMed

Titel: VAV2, a guanine nucleotide exchange factor for Rac1, regulates glucose-stimulated insulin secretion in pancreatic beta cells
verfasst von: Rajakrishnan Veluthakal
Ragadeepthi Tunduguru
Daleep Kumar Arora
Vaibhav Sidarala
Khadija Syeda
Cornelis P. Vlaar
Debbie C. Thurmond
Anjaneyulu Kowluru
Publikationsdatum: 01.11.2015
Verlag: Springer Berlin Heidelberg
Erschienen in: Diabetologia / Ausgabe 11/2015
Print ISSN: 0012-186X
Elektronische ISSN: 1432-0428
DOI: https://doi.org/10.1007/s00125-015-3707-4

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Aims/hypothesis

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