BIO 102 Unit 4 Part 2_ Cytoskeleton Notes

For actin fluorescently tag actin subunit linear line

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: oo thing) 4. for actin: fluorescently tag actin subunit Linear line! x-inter cept is critical concentration S lide 59: [polymer] at steady state: 1.8 T otal subunit concentration= equib-polymer (2-0.2) Nucleat ion is a 2- st ep react ion: --creates a dimer (unstable) --then another comes in, adds a tr imer (<--- nucleus) --can add more subunits on to both ends to form a filament C. Key Feat ures of act in/ MT A ssembly -during the elongation, phase rate of polymer elongation is linear - linearly dependent on total subunit concentration -rate of polymer along. is faster at the plus/barbed end than at the pointed (minus) end of the polymer -the cr it concentr ation for subunit addition is low er at the plus end than at the minus end (bias of subunit adding) -plus end is the fast disassembly end for both MTs and actin filaments aka plus end grows faster and at a lower crit concentration D. Key Feat ures of MT/ act in MT assembly : Lag in hy droly sis of bound nucleot ide aft er subunit addit ion t o poly mer -for both G-actin and tubulin dimer, nucleotide (NTP) hydrolysis occurs upon incorpor ation into polymer -how ever, hydrolysis occurs at a r ate slow er than subunit addition under conditions of high free subunits available for addition Actin filaments “age” from +‐>‐ end after subunit addition at the + end because AT P hydr olysis and then release of Pi are slow processes As a gr ow ing filament ages, subunits in the oldest par t of the filament will contain...
View Full Document

Ask a homework question - tutors are online