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C F Asnes

Publications and source records attributed to C F Asnes.

10 recordsLinked to original sources
PubMed1984

MAP 4: occurrence in mouse tissues.

A polyclonal antiserum to a microtubule-associated protein (MAP) from mouse neuroblastoma cells (MAP 4) was used to examine the distribution of this protein in mouse tissues. Immunoblots of neuroblastoma cell microtubule protein preparations demonstrated that the antiserum reacted with a triplet of proteins at 215,000-240,000 mol wt. Antibodies affinity purified from any of the bands showed cross-reaction with the other bands, indicating these polypeptides were all immunologically related. Antibodies specific to MAP 4 decorated microtubules in cultured murine cells fixed with glutaraldehyde, and diffuse staining was seen following treatment of cells with nocodazole. The antiserum reacted with MAP 4 in extracts of brain, heart, liver, and lung from adult mouse; the triplet in brain was more closely spaced than in the other tissues or neuroblastoma cells. In kidney, spleen, and stomach, only a single band (band 4) was labeled; this band was immunologically related to the triplet and was also present in all tissues positive for the triplet. Skeletal muscle, sperm, and peripheral blood contained no reactive polypeptides. After taxol-induced polymerization, the MAP 4 triplet was preferentially associated with the microtubule pellet whereas band 4 remained in the supernatant. These data indicate that there is tissue specificity in the distribution of MAP 4, and that some tissues contain a polypeptide related to MAP 4 (band 4) that does not bind to microtubules in vitro.

Animals↗
PubMed1983

Taxol binds differentially to flagellar outer doublets and their reassembled microtubules.

Taxol induces the in vitro assembly of calcium stable microtubules from flagellar tubulin solubilized from sea urchin (Strongylocentrotus purpuratus) sperm tail outer doublets by sonication. Assembly occurs in the presence or absence of exogenous GTP. The drug (10 microM) reduces the critical concentration of protein required for assembly to less than or equal to 0.04 mg/ml. 3H-Taxol binds specifically to both isolated flagellar outer doublets and to reassembled microtubules with calculated maximal binding ratios of 0.25 and 1.32 moles taxol/mole polymerized flagellar tubulin dimer, respectively. We suggest that the discrepancy in maximal binding ratios may result from the presence of an endogenous molecule(s) along the surface of outer doublet microtubules that restricts taxol binding to that structure.

Alkaloids↗
PubMed1976

Properties of tubulin in unfertilized sea urchin eggs. Quantitation and characterization by the colchicine-binding reaction.

The colchicine-binding assay was used to quantitate the tubulin concentration in unfertilized Strongylocentrotus purpuratus eggs and to characterize pharmacological properties of this tubulin. Specificity of colchicine binding to tubulin was demonstrated by apparent first-order decay colchicine-binding activity with stabilization by vinblastine sulfate, time and temperature dependence of the reaction, competitive inhibition by podophyllotoxin, and lack of effect of lumicolchicine. The results demonstrate that the minimum tubulin concentration in the unfertilized egg is 2.71 mg per milliliter or 5.0% of the total soluble cell protein. Binding constants and decay rates were determined at six different temperatures between 8 degrees C and 37 degrees C, and the thermodynamic parameters of the reaction were calculated. delta H0=6.6 kcal/mol, delta S0=46.5 eu, and, at 13 degrees C, delta G=-6.7 kcal/mol. The association constants obtained were similar to those of isolated sea urchin egg vinblastine paracrystals (Bryan, J. 1972. Biochemistry. 11:2611-2616) but approximately 10 times lower than that obtained for purified chick embryo brain tubulin at 37 degrees C (Wilson, L.J.R. Bamburg, S.B. Mizel, L. Grisham, and K. Creswell. 1974. Fed Proc. 33:158-166). Therefore, the lower binding constants for colchicine in tubulin-vinblastine paracrystals are not due to the paracrystalline organization of the tubulin, but are properties of the sea urchin egg tubulin itself.

Animals↗