S100a0 Protein Research Articles

S100A1: a physiological modulator of RYR1, Ca2+ release, and contractility in skeletal muscle. Focus on “S100A1 promotes action potential-initiated calcium release flux and force production in skeletal muscle”

SKELETAL MUSCLES adjust their contractile output over an exceptionally wide dynamic range, as needed to produce movements ranging from sitting and standing, to athletics and dance. At the single fiber level, the force generated by skeletal muscles is determined, ultimately, by the formation of cycling cross bridges between actin and myosin. This interaction requires Ca 2 and is governed by the simple relationship: force is proportional to intracellular ionized Ca 2 . Cross-bridge formation is inhibited in resting muscle when Ca 2 is sequestered within the sarcoplasmic reticulum (SR); it is activated when stored Ca 2 is released into the cytosol, allowing actin-myosin interactions to proceed. Contraction stops as Ca 2 is actively resequestered by the Ca 2 -ATPase of the SR (SERCA1). Thus Ca 2 is the central messenger in muscle activation, and the amplitude and time course of the intracellular Ca 2 change is the major determinant of contractile output. The key mechanisms that activate Ca 2 release from the SR are now well defined. This sequence, termed excitation-contraction coupling, begins when an excitatory input from the motor nerve triggers a propagating action potential on the muscle membrane. The action potential rapidly depolarizes the entire sarcolemma, including transverse tubules, which invaginate from the surface membrane and form specialized junctions (triads) with the SR along much of their length. The triad junction serves as a platform for assembling sarcolemmal calcium

S100a0 protein as a marker for tissue damage related to extracorporeal shock wave lithotripsy.

We assayed serum and urine S100a0 protein levels in patients with renal stones (n = 21) or ureteral stones (n = 18), before and after extracorporeal shock wave lithotripsy (ESWL) to evaluate tissue injury. Serum S100a0 protein levels increased significantly immediately after, and at 2 and 24 h after ESWL in patients with renal stones, and at 2 and 24 h after ESWL in patients with ureteral stones. Significant increases in urine S100a0 protein levels were observed immediately and 2 h after ESWL in both groups of patients. The patients receiving a higher number of shock waves had a more pronounced increase in serum S100a0 protein especially in the case of more than 3,500 shock waves. Because S100a0 protein exists at relatively high concentrations in the proximal renal tubules and skeletal muscles, serum and urine S100a0 protein levels appear to be useful markers of tissue injury, including damage in the kidney and skeletal muscles, in the early post-ESWL phase.

ESWLによる組織損傷のマーカーとしてのS100a0 protein, creatine kinase isozymes の有用性について

In order to demonstrate that the extracorporeal shockwave lithotripsy (ESWL) for urolithiasis causes a renal damage, we immunoassayed S100a0 protein and creatine kinase isozymes (CK-B & CK-M) in the serum and urine from patients with renal stone (N = 21) and those with ureteral stone (N = 18) before and after ESWL. S100a0 protein and CK-B, which are localized in the proximal renal tubules at relatively high concentrations, were enhanced more or less both in the urine and serum samples after the treatment in both groups of patients. Since CK-M, which is mainly localized in muscle tissue, also increased in both groups of patients, S100a0 protein and CK-B may be derived not only from kidney, but also from muscle tissues.

S-100ao protein in blood and urine during open-heart surgery.

Concentrations of S100a0 protein and CK-MB were measured by enzyme immunoassay in serial samples of arterial and coronary-sinus blood and urine taken from 26 patients who were undergoing mitral valve surgery. The mean concentration of arterial S100a0 in plasma was 0.32 (SD 0.28) ng/mL at the beginning of anesthesia, increased sharply after reperfusion, peaking [14.4 (SD 6.63) ng/mL] after 45 min of reperfusion, then decreased rapidly. The concentration of creatine kinase (CK) isoenzyme MB in arterial blood plasma was greatest 3 h after reperfusion [107 (SD 54.5) ng/mL]. S100a0 concentrations in urine increased dramatically after reperfusion [16,300 (SD 12,000) ng/h vs 44 (SD 32) ng/h], while CK-MB increased slightly [135 (SD 75) ng/h vs 19 (SD 12) ng/h]. These results suggest that S100a0 in cardiac muscle is released into the bloodstream during open-heart surgery and is discharged into the urine more rapidly than is CK-MB. Determination of S100a0 in plasma or urine thus may be useful for estimating damage to heart muscle during open-heart surgery.

Effects of Ca 2+ and Zn 2+ on trifluoperazine-S100 proteins interactions: Induced circular dichroism and fluorescence spectra

Interactions of trifluoperazine (TFP) with S100 proteins, EF-hand type Ca2+-binding proteins, in the presence of Ca2+ and Zn2+ were studied with induced circular dichroism (CD) and fluorescence spectra. The positive CD bands of TFP were induced at around 265 nm by adding either S100a or S100a0 protein in the presence of Ca2+. No CD band of TFP was, however, induced by adding S100b protein in the presence of Ca2+. Addition of Zn2+ to the TFP/S100 protein solutions did not induce any CD band at all. The fluorescence intensity of 2-p-toluidinylnaphthalene 6-sulfonate (TNS) bound to S100a or S100a0 protein decreased by adding TFP in the presence of Ca2+, while that bound to S100b protein decreased by adding TFP in the presence of Zn2+, indicating that TFP binds to S100a protein and S100a0 protein in a Ca2+-dependent manner and to S100b protein in a Zn2+-dependent manner. From these results together with other experimental findings it was suggested that (1) TFP binds to S100a protein and S100a0 protein in the presence of Ca2+, with half-saturation points of 18 and 3 microM, respectively, (2) TFP binds to S100b protein only in the presence of Zn2+, (3) alpha-subunit of S100 protein binds to TFP specifically in a Ca2+-dependent manner and beta-subunit in a Zn2+-dependent manner.

S-100a0 protein stimulates the basal (Mg2+-activated) adenylate cyclase activity associated with skeletal muscle membranes

S-100a0, protein, the αα isoform of the S-100 family, stimulates basal (Mg2+-activated) adenylate cyclase (AC) activity associated with the sarcolemma, longitudinal tubules and terminal cisternae of rat skeletal muscle cells. The stimulatory effect of S-100a0 on AC activity is maximal around 5μM S-100a0 and half-maximal around 0.2 μM S-100a0. Also, the stimulatory effect is greatest on the AC activity associated with the terminal cisternae than on the other membrane fractions studied. These data are discussed in relation to the subcellular localization of S-100a0 in muscle cells.

A rapid and simple method for the isolation of S100a0 (αα) protein by high-performance liquid chromatography

A rapid and simple method to isolate S100a(0) protein from the mixture of bovine S100 protein (S100a(0), S100a and S100b) is described. The S100 mixture purified from bovine brain was applied to an anion-exchange column, equilibrated with 50 mM Tris HC1 buffer (pH 8.0) in a high-performance liquid chromatography (HPLC) system. S100a(0), S100a and S100b proteins could be eluted separately from the column, which were identified by the immunoassay method, by the Tris-HC1 buffer containing a linear concentration gradient (0.25-0.4) M of NaCl. Immunoreactive S100a(0) protein was found in two peak fractions, and each S100a(0) fraction could be isolated (S100a(0)-1 and S100a(0)-2). Both fractions of S100a(0) protein showed a single band at the same position on acrylamide gel electrophoresis, and eluted in a single peak in the same fractions upon gel-filtration column chromatography. There was no significant difference in the amino acid composition between the two S100a(0) fractions. Since the S100a(0)-1 fraction aged for several months at 4 degrees C in the presence of 0.1% NaN(3) was found to contain four protein peaks including the fraction corresponding to the S100a(0)-2 fraction, the difference between the two S100a(0) fractions is probably due to some modification of amino acid residues in the molecule, which may occur both in vivo and in vitro.

S100a0 (alpha alpha) protein is present in neurons of the central and peripheral nervous system.

The cellular distribution of S100 subunits in human brain and peripheral nerves was studied by means of an immunohistochemical technique using antibodies specific to the alpha subunit or the beta subunit of S100 protein. The results indicate that the distribution of the alpha subunit and the beta subunit is different among cell types in the nervous tissue, and that neurons in the brain and peripheral nerves contain only the alpha subunit, or S100a0 protein. The subunit distribution also appears to be different at an intracellular level, where the immunoreaction products for the alpha subunit show granular arrangement whereas those for the beta subunit are found diffusely in the cytoplasm.