Therefore, the ATP-promoted KIF3CC mechanism of catastrophe is different from the well-described catastrophe factors kinesin-13 MCAK and kinesin-8 Kip3/KIF18A.
Thus, both kinesins are catastrophe factors; Kip3 mediates fine control of microtubule length by narrowing the distribution of maximum lengths prior to catastrophe, whereas MCAK promotes rapid restructuring of the microtubule cytoskeleton by making catastrophe a first-order random process.
Recent studies show that the kinetics of microtubule catastrophes in vitro is a multi-step process that is regulated by kinesin-8 and kinesin-13 motors, which are hypothesized to act as catastrophe factors (Gardner et al., 2011).
As for these regulators in cancer cells, the catastrophe factors of MTs such as oncoprotein (Op 18/stathmin were reported to be overexpressed in a number of human malignancies, and to be associated with cancer progression and prognosis (Roos et al, 1993; Bieche et al, 1998a, 1998b; Brattsand, 2000; Chen et al, 2003; Moore and Wordeman, 2004; Kouzu et al, 2006).
We can see that the catastrophe progression and safety factor have an approximately similar change law: the safety factor increases (decreases) with the catastrophe progression value in a similar way.
A comparison between the catastrophe progression and safety factor of embankment slope is shown in Fig. 4.
On a slightly different vein, Sidaya (2006) carried out a study whose main purpose was to analyze what strategies small and medium businesses actually adopt when confronted with a major crisis such as a fire, flood, or similar catastrophe and determine what factors proved vital to the survival of the business in Australia.
So let's hope that assignment editors and headline writers can eventually get over their knee-jerk categorizing, and be educated to fully recognize the human-made element that's so often a critical factor in catastrophes.
Previous studies make conflicting claims about the dependency of mitotic catastrophe on specific SAC factors: one study reported that BubR1 and Mad2 are indispensable for mitotic catastrophe induced by inhibition of Chk1, whereas another reported that Mad2 is required for mitotic catastrophe induced by Glyfoline, which does not bind DNA and does not affect tubulin polymerization.
Open image in new window Fig. 4 The change law of catastrophe progression value and safety factor.
