HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 276, Issue 44, 41112-41119, November 2, 2001

This Article Full Text Full Text (PDF) All Versions of this Article: 276/44/41112    most recent M106209200v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Fukuda, M. Articles by Mikoshiba, K. Search for Related Content PubMed PubMed Citation Articles by Fukuda, M. Articles by Mikoshiba, K. Social Bookmarking                      What's this?

Formation of Crystalloid Endoplasmic Reticulum Induced by Expression of Synaptotagmin Lacking the Conserved WHXL Motif in the C Terminus
STRUCTURAL IMPORTANCE OF THE WHXL MOTIF IN THE C2B DOMAIN^*

Mitsunori Fukuda^§, Akitsugu Yamamoto^¶, and Katsuhiko Mikoshiba

From the  Laboratory for Developmental Neurobiology, Brain Science Institute, RIKEN (The Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako, Saitama 351-0198, the ^¶ Department of Physiology, Kansai Medical University, Moriguchi, Osaka 570-8506, and the  Department of Basic Medical Science, Division of Molecular Neurobiology, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan

Synaptotagmin (Syt) is a family of type I membrane proteins that consists of a single transmembrane domain, a spacer domain, two Ca²⁺-binding C2 domains, and a short C terminus. We recently showed that deletion of the short C terminus (17 amino acids) of Syt IV prevented the Golgi localization of Syt IV proteins in PC12 cells and induced granular structures of various sizes in the cell body by an unknown mechanism (Fukuda, M., Ibata, K., and Mikoshiba, K. (2001) J. Neurochem. 77, 730-740). In this study we showed by electron microscopy that these structures are crystalloid endoplasmic reticulum (ER), analyzed the mechanism of its induction, and demonstrated that: (a) mutation or deletion of the evolutionarily conserved WHXL motif in the C terminus of the synaptotagmin family (Syt C) destabilizes the C2B domain structure (i.e. causes misfolding of the protein), probably by disrupting the formation of stable anti-parallel -sheets between the -1 and -8 strands of the C2B domain; (b) the resulting malfolded proteins accumulate in the ER rather than being transported to other membrane structures (e.g. the Golgi apparatus), with the malfolded proteins also inducing the expression of BiP (immunoglobulin binding protein), one of the ER stress proteins; and (c) the ERs in which the Syt C proteins have accumulated associate with each other as a result of oligomerization capacity of the synaptotagmin family, because the Syt IC mutant, which lacks oligomerization activity, cannot induce crystalloid ER. Our findings indicate that the conserved WHXL motif is important not only for protein interaction site but for proper folding of the C2B domain.

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

This article has been cited by other articles:

				B. Bhattacharya and P. Roy Bluetongue Virus Outer Capsid Protein VP5 Interacts with Membrane Lipid Rafts via a SNARE Domain J. Virol., November 1, 2008; 82(21): 10600 - 10612. [Abstract] [Full Text] [PDF]

				R. Amarilio, S. Ramachandran, H. Sabanay, and S. Lev Differential Regulation of Endoplasmic Reticulum Structure through VAP-Nir Protein Interaction J. Biol. Chem., February 18, 2005; 280(7): 5934 - 5944. [Abstract] [Full Text] [PDF]

				R. R. Llinas, M. Sugimori, K. A. Moran, J. E. Moreira, and M. Fukuda Vesicular reuptake inhibition by a synaptotagmin I C2B domain antibody at the squid giant synapse PNAS, December 21, 2004; 101(51): 17855 - 17860. [Abstract] [Full Text] [PDF]

				M. Fukuda, E. Kanno, M. Satoh, C. Saegusa, and A. Yamamoto Synaptotagmin VII Is Targeted to Dense-core Vesicles and Regulates Their Ca2+-dependent Exocytosis in PC12 Cells J. Biol. Chem., December 10, 2004; 279(50): 52677 - 52684. [Abstract] [Full Text] [PDF]

				M. Fukuda and A. Yamamoto Effect of Forskolin on Synaptotagmin IV Protein Trafficking in PC12 Cells J. Biochem., August 1, 2004; 136(2): 245 - 253. [Abstract] [Full Text] [PDF]

				M. Fukuda and T. Itoh Slac2-a/Melanophilin Contains Multiple PEST-like Sequences That Are Highly Sensitive to Proteolysis J. Biol. Chem., May 21, 2004; 279(21): 22314 - 22321. [Abstract] [Full Text] [PDF]

				E. L. Snapp, R. S. Hegde, M. Francolini, F. Lombardo, S. Colombo, E. Pedrazzini, N. Borgese, and J. Lippincott-Schwartz Formation of stacked ER cisternae by low affinity protein interactions J. Cell Biol., October 27, 2003; 163(2): 257 - 269. [Abstract] [Full Text] [PDF]

				M. Fukuda Molecular Cloning, Expression, and Characterization of a Novel Class of Synaptotagmin (Syt XIV) Conserved from Drosophila to Humans J. Biochem., May 1, 2003; 133(5): 641 - 649. [Abstract] [Full Text] [PDF]

				M. Fukuda, E. Kanno, Y. Ogata, C. Saegusa, T. Kim, Y. P. Loh, and A. Yamamoto Nerve Growth Factor-dependent Sorting of Synaptotagmin IV Protein to Mature Dense-core Vesicles That Undergo Calcium-dependent Exocytosis in PC12 Cells J. Biol. Chem., January 24, 2003; 278(5): 3220 - 3226. [Abstract] [Full Text] [PDF]

				M. Fukuda Synaptotagmin-like Protein (Slp) Homology Domain 1 of Slac2-a/Melanophilin Is a Critical Determinant of GTP-dependent Specific Binding to Rab27A J. Biol. Chem., October 11, 2002; 277(42): 40118 - 40124. [Abstract] [Full Text] [PDF]

				M. Fukuda Vesicle-associated Membrane Protein-2/Synaptobrevin Binding to Synaptotagmin I Promotes O-Glycosylation of Synaptotagmin I J. Biol. Chem., August 9, 2002; 277(33): 30351 - 30358. [Abstract] [Full Text] [PDF]

				C. Saegusa, M. Fukuda, and K. Mikoshiba Synaptotagmin V Is Targeted to Dense-core Vesicles That Undergo Calcium-dependent Exocytosis in PC12 Cells J. Biol. Chem., June 28, 2002; 277(27): 24499 - 24505. [Abstract] [Full Text] [PDF]