Abstract
CalDAGs are a family of Ras guanyl exchange factors that contain calcium and DAG-binding domains. Among the four identified members of CalDAG family, CalDAGIII has been shown to play important role in B lymphocyte and endocrine cell functions. However, the mechanism underlining these functions remain to be determined. Here in the present study, we determined the subcellular localization of CalDAGIII and roles of calcium-binding and DAG-binding domains in its localization. We found that C1 domain but not EF hands is important for both CalDAGIII localization to the Golgi and p38 activation in B cells, indicating that CalDAGIII may be regulated by DAG but not Calcium.
Similar content being viewed by others
References
Lambert QT, Reuther GW (2006) Activation of Ras proteins by Ras guanine nucleotide releasing protein family members. Methods Enzymol 407:82
Springett GM, Kawasaki H, Spriggs DR (2004) Non-kinase second-messenger signaling: new pathways with new promise. Bioessays 26:730
Clyde-Smith J, Silins G, Gartside M, Grimmond S, Etheridge M, Apolloni A, Hayward N, Hancock JF (2000) Characterization of RasGRP2, a plasma membrane-targeted, dual specificity Ras/Rap exchange factor. J Biol Chem 275:32260
Kawasaki H, Springett GM, Toki S, Canales JJ, Harlan P, Blumenstiel JP, Chen EJ, Bany IA, Mochizuki N, Ashbacher A, Matsuda M, Housman DE, Graybiel AM (1998) A Rap guanine nucleotide exchange factor enriched highly in the basal ganglia. Proc Natl Acad Sci USA 95:13278
Crittenden JR, Bergmeier W, Zhang Y, Piffath CL, Liang Y, Wagner DD, Housman DE, Graybiel AM (2004) CalDAG-GEFI integrates signaling for platelet aggregation and thrombus formation. Nat Med 10:982
Dupuy AJ, Morgan K, von Lintig FC, Shen H, Acar H, Hasz DE, Jenkins NA, Copeland NG, Boss GR, Largaespada DA (2001) Activation of the Rap1 guanine nucleotide exchange gene, CalDAG-GEF I, in BXH-2 murine myeloid leukemia. J Biol Chem 276:11804
Yamashita S, Mochizuki N, Ohba Y, Tobiume M, Okada Y, Sawa H, Nagashima K, Matsuda M (2000) CalDAG-GEFIII activation of Ras, R-Ras, and Rap1. J Biol Chem 275:25488
Dower NA, Stang SL, Bottorff DA, Ebinu JO, Dickie P, Ostergaard HL, Stone JC (2000) RasGRP is essential for mouse thymocyte differentiation and TCR signaling. Nat Immunol 1:317
Ebinu JO, Bottorff DA, Chan EY, Stang SL, Dunn RJ, Stone JC (1998) RasGRP, a Ras guanyl nucleotide-releasing protein with calcium- and diacylglycerol-binding motifs. Science 280:1082
Oh-hora M, Johmura S, Hashimoto A, Hikida M, Kurosaki T (2003) Requirement for Ras guanine nucleotide releasing protein 3 in coupling phospholipase C-gamma2 to Ras in B cell receptor signaling. J Exp Med 198:1841
Ozaki N, Miura Y, Yamada T, Kato Y, Oiso Y (2005) RasGRP3 mediates phorbol ester-induced, protein kinase C-independent exocytosis. Biochem Biophys Res Commun 329:765
Bivona TG, Perez de Castro I, Ahearn IM, Grana TM, Chiu VK, Lockyer PJ, Cullen PJ, Pellicer A, Cox AD, Philips MR (2003) Phospholipase C[gamma] activates Ras on the Golgi apparatus by means of RasGRP1. Nature 424:694
Stahelin RV, Rafter JD, Das S, Cho W (2003) The molecular basis of differential subcellular localization of C2 domains of protein kinase C-alpha and group IVa cytosolic phospholipase A2. J Biol Chem 278:12452
Carrasco S, Merida I (2004) Diacylglycerol-dependent binding recruits PKC{theta} and RasGRP1 C1 domains to specific subcellular localizations in living T lymphocytes. Mol Biol Cell 15:2932