BIOL 2021 Lecture Notes - Lecture 18: Cell Division, Actomyosin Ring, Red Blood Cell
12 May 2013
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Kinetochoremicrotubules attach sister chromatids to opposide poles. Astral: radiate outward from centrosomes to cell cortex. G1/s cdk centrosome duplication: beginning of s phase. Beginning of m-phase: m-cdk phosphorylates, maps, catastrophe factors microtubules become shorter and more dynamic, m-cdk can other kinases phosphorylate centrosome, get more gamma tubulin ring complexes, more microtubules, m-cdk phosphorylates motor proteins. Motor proteins in the spindle: figure 17-30, dyenin tries to walk to minus end, pulling microtubules to the cortex. Anaphase: activation of apc (anaphase promoting complex, when this is activated - fig 17-43*, activation pathway: Cdc 20 activates apc cdc20 gene transcription more cdc20 protein. Phosphorylate apc by m-cdk help cdc20 bind. Active separase cleaves cohesin allows sister chromatins to separate. Normally, cohesin holds chormatids together at end of s-phase fig 17- Apc also targets all other s-cyclins and m-cyclins, marking them for destruction (cdks have been inactivate) M-cdk causes its own inactivation and destruction negative feedback.
