A role for CCN3 (NOV) in calcium signalling

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• CCN3 (NOV) expression is elevated in tissues where calcium regulation is critical, including the adrenal gland, CNS, bone, cartilage, heart, and kidney.
• The structure of CCN proteins suggests they are metalloproteins, prompting investigation into CCN3's role in ion flux and cellular processes.

Purpose of the Study:

• To investigate the role of CCN3 in ion flux and transport during development.
• To explore CCN3's involvement in the control of cell proliferation, differentiation, and pathobiology.
• To identify CCN3's interaction partners and its effect on intracellular calcium concentrations.

Main Methods:

• Utilized a yeast two-hybrid system to identify CCN3 interaction partners, followed by GST pull-down assays to confirm interactions.
• Employed dynamic imaging microscopy for fluorometric measurement of intracellular calcium concentration.
• Tested the effects of CCN3 and CCN2 (CTGF) on calcium flux in glioblastoma and neuroblastoma cell lines.

Main Results:

• Identified S100A4, a calcium-binding protein, as a binding partner of CCN3.
• Demonstrated that CCN3 and CCN2 induce a transient increase in intracellular calcium in G59 glioblastoma and SK-N-SH neuroblastoma cells.
• Observed that calcium originates from both extracellular entry and intracellular stores upon CCN3/CCN2 stimulation.

Conclusions:

• The interaction between CCN3 and S100A4 may explain CCN3's association with carcinogenesis and its expression patterns.
• CCN3 and CCN2-induced calcium increases involve voltage-independent calcium channels, suggesting a role in cell growth, motility, and spreading.
• This study establishes a biological function for CCN3 and highlights the broader role of CCN proteins in calcium signaling.