Disease relevance of S100A5

• S100A5: a marker of recurrence in WHO grade I meningiomas [1].
• Further, the carcinomas tested were originated probably not in the S100A5-positive distal epithelium but in the -negative epithelium of proximal tubules [2].
• Reverse transcription--polymerase chain reaction (RT-PCR) identified the expression of calcium-binding protein S100A5 in the noncancerous parts of resected samples from renal cell carcinoma (RCC) patients (n = 7) but not in the carcinoma lesions [2].

High impact information on S100A5

• The product of S100E is cysteine-rich, whereas that of S100D contains a long hydrophobic N-terminal tail [3].
• Six S100 genes are clustered on human chromosome 1q21: identification of two genes coding for the two previously unreported calcium-binding proteins S100D and S100E [3].
• While the S100A5 protein was significantly expressed in all the astrocytic tumors (but without any significant modifications in the levels of malignancy), the S100A2 protein was never expressed in these tumors [4].
• Flow dialysis revealed that the homodimeric S100A5 binds four Ca(2+) ions with strong positive cooperativity and an affinity 20-100-fold higher than the other S100 proteins studied under identical conditions [5].
• S100A5 also binds two Zn(2+) ions and four Cu(2+) ions per dimer [5].

Biological context of S100A5

• S100A5 is a novel member of the EF-hand superfamily of calcium-binding proteins that is poorly characterized at the protein level [5].
• The potential role of S100A5 in copper homeostasis is discussed [5].

Anatomical context of S100A5

• At 12 weeks, S100A5 was strongly expressed in the cells and fibers of the polymorphic, pyramidal, and molecular layers of the hippocampus [6].
• From birth onwards, S100A5 remained a neuronal-specific protein, only located in a subpopulation of neurons in the spiral ganglion [7].
• Immunolocalization of the calcium binding S100A1, S100A5 and S100A6 proteins in the dog cochlea during postnatal development [7].
• Dendritic cells were identified using S100 immunohistochemistry, and their peritumor and intratumor density (peri-S100D and intra-S100D) were determined [8].

Associations of S100A5 with chemical compounds

• Here we characterized the human recombinant S100A5, especially its interaction with Ca(2+), Zn(2+), and Cu(2+) [5].
• Thus, it was suggested that S100A5 protein plays an inherent functional role to the post-thick ascending limb of Henle portion in the nephron [2].
• Then, total RNA was extracted by phenol/chloroform from 1 ml urine of healthy volunteers, and S100A5 was amplified by RT-PCR from all samples (n = 12), indicating that the transcript of S100A5 is detectable even in the cells released into urine [2].

Other interactions of S100A5

• S100A3 and S100A6 and, to a lesser extent, S100A5 were the most differentially expressed proteins across the different histopathological groups analysed [9].
• First we identified the cDNA sequences of mouse S100A1, S100A3 and S100A5 [10].
• In contrast, S100A5 and S100A12 were not significantly expressed in any of the tumor tissues tested [11].
• Using 63 meningiomas (39 benign and 24 atypical), we performed a semi-quantitative histochemical analysis of both the expression of galectin-3 and its ligand profile and the Ca2+-binding proteins S100A5, S100A6 and S100B [12].
• In sharp contrast, the levels of expression of the S100A3 and S100A5 proteins differed markedly in the solid tumour tissue in relation to the astrocytic tumour types and grades [13].

References