Isolation and Characterization of Profilactin and Profilin from Calf Thymus and Brain

Abstract

Profilactin and profilin have been purified from calf thymus and calf brain. Thymus profilactin could be crystallized with a similar technique as described earlier for the spleen protein. Preparations of profilactin from the three calf tissues spleen, thymus and brain contain a mixture of β actin and γ actin. The ratio β/γ differs between the tissues, but is constant throughout the purification steps. The properties of profilin isolated from three sources (spleen, thymus and brain) indicate that it is a highly conserved protein.

Cell-Specific Expression of a Profilin Gene Family

“…Profilin was first isolated from calf spleen (Carlsson et al, 1977) and subsequently found in a variety of other vertebrate tissues (Blikstad et al, 1980;Fattoum et al, 1980;Ohshima et al, 1989). A similar protein was isolated from the invertebrates Acanthamoeba castellana (Ampe et al, 1985;Kaiser et al, 1986;Ampe et al, 1988), P. polycephalum (Osaki et al, 1983;Osaki and Hatano, 1984), and Thyone briareus (Tilney et al, 1983).…”

Mechanism of action of Acanthamoeba profilin: demonstration of actin species specificity and regulation by micromolar concentrations of MgCl2.

“…With 30 pM platelet profdin there was no inhibition in 2 mM MgClz. However 34/zM spleen, brain, or thymus profdin all inhibited the steady-state viscosity of muscle actin >90% in 2 mM CaCI2 (2). There were no experiments to test whether the buffer composition (especially the divalent cation) might explain these differences.…”

“…It is difficult to compare the four different published studies, because there is no uniformity in the buffer conditions or the concentration or type of actin. In five published experiments using 14 to 18 tzM muscle actin in phosphate buffer with 2 mM MgCI2 or CaC12, 8 to 12 btM profilin from brain, spleen, thymus (2), or platelets (9) inhibited the steady-state viscosity <20%. With 30 pM platelet profdin there was no inhibition in 2 mM MgClz.…”

Cloning and expression of a novel human profilin variant, profilin II

“…Profilin is a 12-15 kDa protein that initially was isolated from bovine spleen [l] and subsequently found to be expressed in several mammalian tissues such as thymus, brain, platelets [2][3][4], thyroid gland [5], macrophages [6], liver, spleen, uterus, heart, lung and kidney [7]. Human profilin shows 95% identity to bovine profilin and the amino acid exchanges are mainly conservative [7].…”