Identification of a membrane bound fraction of the S-100 protein

The Amino‐Acid Sequence of S‐100 Protein (PAP I‐b Protein) and Its Relation to the Calcium‐Binding Proteins

“…The protein chain consists of 91 amino acid residues and has a molecular weight of 10507. The sequence shows regions of strong clustering of hydrophobic, basic and acidic amino acids, with an apparent calcium-binding site in the acidic cluster.S-100 protein is a brain-specific protein [l], found mainly in the cytoplasm of glial cells and partially in the nuclei of neurons [2 -51, as well as in a form bound to the membrane [6,7]. The biological function of this protein is unknown, but previous results suggest a role for this protein in the function or development of the nervous system [3,8 -11 1.…”

“…S-100 protein is a brain-specific protein [l], found mainly in the cytoplasm of glial cells and partially in the nuclei of neurons [2 -51, as well as in a form bound to the membrane [6,7]. The biological function of this protein is unknown, but previous results suggest a role for this protein in the function or development of the nervous system [3,8 -11 1.…”

S-100 Protein in Guinea Pig Brain during Prenatal Development

“…1). Similar accu mulation curves were obtained for 2 M NaClextractable, water-soluble and 5% n-pentanol-extractable, water-soluble S-100 parts, re presenting the membrane-associated or bound S-100 [I, 5,13], although no membraneassociated S-100 was found on the 30th pre natal day in any region studied. The amounts in figure 1 arc expressed as percent of brain stem value of 55-day pregnant guinea pigs for the different S-100 species, respectively.…”

“…Earlier studies have shown an accumulation of water-soluble S-100 during postnatal devel opment in the brains of rat [8,12,15], of mouse [4], in the avian optic tectum [3] and in the chick spinal cord [2], S-100 has also been studied during development of the em bryonic chick brain [6], as well as during human fetal development [16]. In this study the relation between water-soluble and mem brane-associated (2 M NaCI-extractable) or bound (5% pentanol-extractable) S-100 [5,13] was studied in quantitative terms in three brain regions during prenatal development of guinea pig. As membrane-associated and membrane-bound S-100 accumulates con comitantly with, although slower than, the water-soluble S-100, membranes seem to acquire the ability to incorporate S-100 during differentiation.…”

A Calcium-Dependent Mechanism for Synapse and Nerve Cell Membrane Modulation

“…It increases considerably during the early postnatal period in many mammals and proceeds to increase slowly in amount during the life cycle (9,10). However, a small amount of the S100 protein is insoluble in water and salt solutions but extractable by n-pentanol, which suggests that it binds to membrane (11,12 the neuronal S100 and 5% of the glia is extractable with pentanol but not with watert.…”