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Giulia Baldini, MD,
Ph.D.
Associate Professor
MD, University of
Trieste, Italy
Ph.D, University of Trieste, Italy
Molecular mechanisms of hormone
secretion
My research investigates the molecular mechanisms that make
regulated and constitutive exocytosis function at different Ca2+ levels. We have
shown that formation of a complex composed of SNAP-25 and Syntaxin 1 at the
plasma membrane and VAMP-2 and Synaptotagmin 1 on the vesicle membrane is
necessary for regulated hormone release in response to elevated Ca2+. We are
studying how these complexes and other related complexes of the constitutive
secretory pathway form at elevated and resting Ca2+ levels, respectively. A
second project investigates whether expression of specific transcription factors
lead to formation, accumulation and Ca2+-regulated release of insulin-containing
dense core granules in unspecialized cells. A third project focuses on the
trafficking and surface expression of melanocortin receptors linked to obesity.
In conjunction with the above projects, we are investigating whether endocrine
cell/neuron-specific SNAP-25 and ubiquitously expressed SNAP-23 have specific
roles in neurite formation. The role of Rab proteins and components of the actin
cytoskeleton in the process of granule accumulation at the cell cortex and at
the neurite tips is part of this investigation.
For our research, we use a combination of biochemical and cell biological
including confocal microscopy and total internal reflection microscopy (TIRFM).
Our general research goals are to understand the functional role of
SNAP-25/SNAP-23 and the mechanisms of granule formation and release by endocrine
cells. These goals are aimed towards helping find new therapies for diseases
such as diabetes mellitus and obesity.
Selected Publications
1) G. Baldini, A. M. Martelli, G. Tabellini, C. Horn, K. Machaca, P. Narducci,
and G. Baldini. Rabphilin localizes with the cell actin cytoskeleton and
stimulates association of granules with F-actin cross-linked by -actinin.
(2005) J. Biol. Chem., in press. [Abstract]
2) E. Chieregatti, M.C. Chika, E. R. Chapman and G. Baldini. SNAP-23 expression
in endocrine cells leads to docking/fusion of granules at low [Ca2+]. (2004)
Mol. Biol. Cell, 15, 1919-1930. [Abstract]
3) D. D Koticha, E. E McCarthy and G. Baldini. Plasma membrane targeting of
SNAP-25 increases its local concentration and is necessary for SNARE complex
formation and regulated exocytosis (2002) J. Cell Sci., 115, 3341-51.
[Abstract]
4) E. Chieregatti, J. W. Witkin, and G. Baldini. SNAP-25 and Synaptotagmin 1
function in Ca2+-dependent reversible docking of granules to the plasma membrane
(2002) Traffic, 3, 496-51. [Abstract]
5) A. M. Martelli, G. Baldini, G.Tabellini, D. K. Koticha, R. Bareggi, and G. Baldini. Rab3A and Rab3D control the total granule number and the fraction of
granules docked at the plasma membrane in PC12 cells. (2000) Traffic, 1, 976-986
[Abstract]
6) D. K. Koticha, S. J. Huddleston, J. W. Witkin and G. Baldini. Role of the
cysteine-rich domain of the t-SNARE component, syndet, in membrane binding and
subcellular localization. (1999) J. Biol. Chem., 274, 9053-9060.
[Abstract]
7) G. Baldini, G. Baldini, G. Wang, M. Weber, R. Bareggi, M. Zweier, J. W.
Witkin and A. Martelli. Expression of Rab3D N135I inhibits regulated secretion
of ACTH in AtT-20 cells. (1998) J. Cell Biol., 140, 305-313.
[Abstract]
8) G. Wang, J. W. Witkin, G. Hao, V. A. Bankaitis, P. E. Scherer, and G. Baldini.
Syndet is a novel SNAP-25 related protein expressed in many
tissues.
(1997) J. Cell Sci., 110, 505-513. [Abstract]
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E-mail: |
GBaldini@uams.edu |
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Office: |
(501) 526-7793
Biomedical Research
Center B421F |
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Lab: |
(501) 603-1368
Biomedical Research
Center B423 |
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Fax: |
(501) 686-8169 |
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