• Bulletin of the Korean Chemical Society
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• 제34권4호
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• pp.1120-1126
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• 2013

The syndecan family consists of four transmembrane heparan sulfate proteoglycans present in most cell types and each syndecan shares a common structure containing a heparan sulfate modified extracellular domain, a single transmembrane domain and a C-terminal cytoplasmic domain. To get a better understanding of the mechanism and function of syndecan-4 which is one of the syndecan family, it is crucial to investigate its three-dimensional structure. Unfortunately, it is difficult to prepare the peptide because it is membrane-bound protein that transverses the lipid bilayer of the cell membrane. Here, we optimize the expression, purification, and characterization of transmembrane, cytoplasmic and short extracellular domains of syndecan4 (syndecan-4 eTC). Syndecan-4 eTC was successfully obtained with high purity and yield from the M9 medium. The structural information of syndecan-4 eTC was investigated by MALDI-TOF mass (MS) spectrometry, circular dichroism (CD) spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. It was confirmed that syndecan-4 eTC had an ${\alpha}$-helical multimeric structure like transmembrane domain of syndecan-4 (syndecan-4 TM) in membrane environments.

• Bulletin of the Korean Chemical Society
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• 제29권5호
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• pp.1013-1017
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• 2008

Syndecan-3 is a cell-surface heparan sulfate proteoglycan, which performs a variety of functions during cell adhension process. It is also a coreceptor for growth factor, mediating cell-cell and cell-matrix interaction. Syndecan-3 contains a cytoplasmic domain potentially associated with the cytoskeleton. Syndecan-3 is specifically expressed in neuron cell and has related to neuron cell differentiation and development of actin filament in cell migration. Syndecans each have a unique, central, and variable (V) region in their cytoplasmic domains. And that region of syndecan-3 may modulate the interactions of the conserved C1 regions of the cytoplasmic domains by tyrosine phosphorylation. Cytoplasmic domain of syndecan-3 has been synthesized for NMR structural studies. The solution structure of syndecan-3 cytoplasmic domain has been determined by two-dimensional NMR spectroscopy and simulated-annealing calculation. The cytoplasmic domain of the syndecan proteins has a tendency to form a dimmer conformation with a central cavity, however, that of syndecan-3 demonstrated a monomer conformation with a flexible region near C-terminus. The structural information might add knowledge about the structure-function relationships among syndecan proteins.

• 한국자기공명학회:학술대회논문집
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• 한국자기공명학회 2002년도 International Symposium on Magnetic Resonance
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• pp.90-90
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• 2002

Syndecans, transmembrane heparan sulfate proteoglycans, are coreceptors with integrin in cell adhesion process. It forms a ternary signaling complex with protein kinase C and phosphatidylinositol 4,5 bisphosphate (PIP2) for integrin signaling. NMR data indicates that cytoplasmic domain of syndecan-4 (4L) undergoes a conformational transition in the presence of PIP2, forming oligomeric conformation. The structure based on NMR data demonstrated that syndecan-4L itself forms a compact intertwined symmetric dimer with an unusual clamp shape for residues Leu$^{186}$ -Ala$^{195}$ . The molecular surface of the syndecan-4L dimer is highly positively charged. In addition, no inter-subunit NOEs in membrane proximal amino acid resides (Cl region) has been observed, demonstrating that the Cl region is mostly unstructured in syndecan-4L dimmer. However, the complex structure in the presence of PIP2 induced a high order multimeric conformation in solution. In addition, phosphorylation of cytoplasmic domain induces conformational change of syndecan-4, resulting inhibition of PKC signaling. The NMR structural data strongly suggest that PIP2 promotes oligomerization of syndecan-4 cytoplasmic domain for PKC activation and further induces structural reorganization of syndecan for mediating signaling network in cell adhesion procedure.

• 한국자기공명학회논문지
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• 제13권1호
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• pp.1-6
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• 2009

Syndecan-4 cytoplasmic domain was tested to confirm the interactions with the bilayer membrane using $^{31}P$ solid-state NMR measurements. Syndecan-4 was known as a coreceptor with integrins in the cell adhesion. The syndecan-4 V region is not understood of its functional roles and tested its ability of the interaction with multilamellar vesicles. The $^{31}P$ powder pattern was dramatically changed and showed isotropic peak which imply the bilayer membrane changed its topology to the micelle-like structure. Especially, phosphatidylcholine membrane was affected this effect more than phosphatidylethanolamine membrane.

• 한국자기공명학회논문지
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• 제15권1호
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• pp.25-39
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• 2011

Syndecan-4 is a transmembrane heparan sulfate proteoglycan, which is a coreceptor with integrins in cell adhesion. To get better understand the mechanism and function of Syndecan-4, it is critical to elucidate the three-dimensional structure of a single transmembrane spanning region of them. Unfortunately, it is hard to prepare the peptide because syndecan-4 is membrane-bound protein that transverse the lipid bilayer of the cell membrane. Generally, the preparation of transmembrane peptide sample is seriously difficult and time-consuming. In fact, high yield production of transmembrane peptides has been limited by experimental adversities of insufficient yields and low solubility of peptide. Here, we demonstrate experimental processes and results to optimize expression, purification, and NMR measurement condition of Syndecan-4 transmembrane peptide.

• BMB Reports
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• 제43권5호
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• pp.305-310
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• 2010

Syndecans, cell surface heparansulfate proteoglycans, have been proposed to act as cell surface receptors and/or coreceptors to play critical roles in multiple cellular functions. However, recent reports suggest that the function of syndecans can be further extended through shedding, a cleavage of extracellular domain. Shedding constitutes an additional level for controlling the function of syndecans, providing a means to attenuate and/or regulate amplitude and duration of syndecan signals by modulating the activity of syndecans as cell surface receptors. Whether these remaining cleavage products are still capable of functioning as cell surface receptors to efficiently transduce signals inside of cells is not clear. However, shedding transforms cell surface receptor syndecans into soluble forms, which, like growth factors, may act as novel ligands to induce cellular responses by association with other cell surface receptors. It is becoming interestingly evident that shed syndecans also contribute significantly to syndecan functions in cancer biology. This review presents current knowledge about syndecan shedding and its functional significance, particularly in the context of cancer.

• Bulletin of the Korean Chemical Society
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• 제29권12호
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• pp.2449-2452
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• 2008

• BMB Reports
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• 제52권9호
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• pp.554-559
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• 2019

Despite reports suggesting that tissue-resident natural killer (trNK) cells cause ischemic kidney injury, their contribution to the development of tubulointerstitial fibrosis has not been determined. This study hypothesized that the depletion of trNK cells may ameliorate renal fibrosis by affecting transglutaminase 2/syndecan-4 interactions. Aristolochic acid nephropathy (AAN) was induced in C57BL/6 mice as an experimental model of kidney fibrosis. The mice were treated with anti-asialo GM1 (ASGM1) or anti-NK1.1 antibodies to deplete NK cells. Although both ASGM1 and NK1.1 antibodies suppressed renal $NKp46^+DX5^+$ NK cells, renal $NKp46^+DX5^-$ cells were resistant to suppression by ASGM1 or NK1.1 antibodies during the development of tubulointerstitial fibrosis in the AAN-induced mouse model. Western blot analysis showed that both antibodies increased the expression of fibronectin, transglutaminase 2, and syndecan-4. These findings indicate that trNK cells played an exacerbating role in tubulointerstitial fibrosis by activating transglutaminase 2 and syndecan-4 in the AAN-induced mouse model.

• Bulletin of the Korean Chemical Society
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• 제28권9호
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• pp.1549-1552
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• 2007

The cytoplasmic domain of syndecan-4, a type I transmembrane heparan sulfate proteoglycan, was overexpressed as a fused form with the ubiquitin molecule in Escherichia coli, and the fusion protein was purified using immobilized metal affinity chromatography (IMAC). The cytoplasmic domain was released from its fusion partner by using yeast ubiquitin hydrolase (YUH), and subsequently purified by reverse phase chromatography. The integrity of the resulting peptide fragment was checked by MALDI-TOF and NMR spectroscopy. The yield of the peptide was 3.0-1.5 mg per liter in LB or minimal medium, respectively. The recombinant expression and purification of this domain will enable us its structural and functional studies using multidimensional NMR spectroscopy.

• Biomolecules & Therapeutics
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• 제19권3호
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• pp.267-273
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• 2011

Syndecans are membrane-anchored proteoglycans and implicated in the pathogenesis of cancer progression and metastasis. Syndecans also play important roles in interacting with growth factors, extracellular matrix and other cell surface molecules such as IGF-1 receptor. In the present review, we discuss about the syndecan structure, their role in signaling with other receptors, in addition to its general biology. The emerging roles of syndecans in the pathophysiology of human diseases, especially insulin resistance, diabetes and cancer is discussed.