Analysis of CA(2+)-binding S100 proteins in human heart by HPLC-electrospray mass spectrometry

Area of Science:

• Cardiology
• Biochemistry
• Molecular Biology

Background:

• Calcium-dependent processes are crucial for myocardial function.
• Impaired calcium signaling is linked to heart dysfunctions.
• Calcium-binding proteins, such as the S100 family, may mediate these signals.

Purpose of the Study:

• To develop and apply a method for identifying S100 calcium-binding proteins in the human heart.
• To understand the role of S100 proteins in cardiac calcium signaling.

Main Methods:

• Utilized calcium-dependent affinity chromatography for S100 protein purification.
• Employed reverse-phase high-performance liquid chromatography (RP-HPLC).
• Analyzed proteins using electrospray-ionization mass spectrometry (ESI-MS) and liquid secondary ionization/tandem quadrupole mass spectrometry (LS-MS/MS).

Main Results:

• Identified S100 alpha, CACY, and CAPL as the most abundant S100 proteins in the human heart.
• Demonstrated that these identified S100 proteins exist as both monomers and homodimers.
• Established a method to profile S100 protein footprints in cardiac tissue.

Conclusions:

• S100 proteins, specifically S100 alpha, CACY, and CAPL, are significant components of human heart calcium signaling.
• The monomeric and homodimeric forms of these proteins are relevant in the cardiac context.
• This research provides a foundation for further investigation into S100 proteins in cardiovascular health and disease.