Dynamics of Antarctic fish microtubules at low temperatures

Journal Article · Tue Jun 13 00:00:00 EDT 1989 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00438a028· OSTI ID:5443433

Himes, R H; Detrich, III, H W ^[1]

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1. Univ. of Kansas, Lawrence (USA)

The tubulins of Antarctic fishes, purified from brain tissue and depleted of microtubule-associated proteins (MAPs), polymerized efficiently in vitro to yield microtubules at near-physiological and supraphysiological temperatures (5, 10, and 20{degree}C). The dynamics of the microtubules at these temperatures were examined through the use of labeled guanosine 5{prime}-triphosphate (GTP) as a marker for the incorporation, retention, and loss of tubulin dimers. Following attainment of a steady state in microtubule mass at 20{degree}C, the rate of incorporation of ({sup 3}H)GTP (i.e., tubulin dimers) during pulses of constant duration decreased asymptotically toward a constant, nonzero value as the interval prior to label addition to the microtubule solution increased. Concomitant with the decreasing rate of label incorporation, the average length of the microtubules increased, and the number concentration of microtubules decreased. Thus, redistribution of microtubule lengths appears to be responsible for the time-dependent decrease in the rate of tubulin uptake. At each temperature, most of the incorporated label was retained by the microtubules during a subsequent chase with excess unlabeled GTP. In contrast, when microtubules were assembled do novo in the presence of ({alpha}-{sup 32}P)GTP at 5{degree}C and then exposed to a pulse of ({sup 3}H)GTP, the {sup 32}P label was lost over time during a subsequent chase with unlabeled GTP, whereas the {sup 3}H label was retained. Together, these results indicate that the microtubules of Antarctic fishes exhibit, at low temperatures, behaviors consistent both with subunit treadmilling and with dynamic instability and/or microtubule annealing.

• OSTI ID: 5443433
• Journal Information: Biochemistry; (USA), Vol. 28:12; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
MICROTUBULES
TEMPERATURE EFFECTS
PROTEINS
POLYMERIZATION
ANTARCTICA
BRAIN
FISHES
NUCLEOTIDES
PHOSPHORUS 32
TRITIUM COMPOUNDS
ANIMALS
ANTARCTIC REGIONS
AQUATIC ORGANISMS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CELL CONSTITUENTS
CENTRAL NERVOUS SYSTEM
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
HYDROGEN COMPOUNDS
ISOTOPES
LIGHT NUCLEI
NERVOUS SYSTEM
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANS
PHOSPHORUS ISOTOPES
POLAR REGIONS
RADIOISOTOPES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques