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orji`s presentation actin filament

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ORJI JONATHAN ORJI MD, phD Kutaisi 2013 ACTIN FILAMENT

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Page 1: Orji`s presentation actin filament

ORJI JONATHAN ORJIMD, phDKutaisi 2013

ACTIN FILAMENT

Page 2: Orji`s presentation actin filament

Actin filaments are thin and flexible

7 nm in diameterLess rigid than

microtubulesPlus end - fast

growingMinus end - slow

growingMonomers

polymerize into a helical chain

Page 3: Orji`s presentation actin filament

Actin and microtubules polymerize using similar mechanisms

Monomeric actin binds to ATP

Upon polymerization, actin ATPase activity cleaves ATP to ADP

ATP hydrolysis acts as a molecular “clock”

Older actin filaments with ADP are unstable and disassemble

Page 4: Orji`s presentation actin filament

Myosins are actin-based motor proteins

Myosins convert ATP hydrolysis into movement along actin filaments

Many different classes of myosins (>30 in humans)

Some myosins move cargoes, other myosins slide actin (as in muscles)

Actin & ATP binding sites in N-terminal head domain

Page 5: Orji`s presentation actin filament

Contraction is activated by calcium release from the sarcoplasmic reticulum

Page 6: Orji`s presentation actin filament

Contraction is regulated by a Ca+2-mediated change in the conformation of troponin


Regulation of actin filament dynamics in vivo Fig. 16-52, Alberts

Sunday N. Orji

Intermediate filament accumulation can stabilize ... · network of actin, tubulin, and intermediate filament polymers that maintains cell structure, directs cell growth, and transport

C:office new eachingBiochem F 13lecture notesChapter 5 ... F 16/Lecture notes... · back to start of the cycle of catalysis, but note myosin filament has moved relative to actin filament

The actin filament disrupter cytochalasin D activates the

Crenactin forms actin-like double helical filaments regulated by … · F-actin homologue of any other actin-like filament investigated to date. In F-actin, the double helix is stabilised

Cytoskeletal dynamics in vitro Assembly of actin filaments in vitro –The Critical concentration –Treadmilling The regulation of actin filament dynamics

Orji Genius presentation

Muscle Fibers Muscle Tissue and Muscles• Thick filament • Thin filament Thin Filaments • Thin filaments – Consist of the protein actin and two associated proteins, troponin

Motor mechanisms. Keywords (reading p. 1014- 1020) Bundle, fiber, myofibril, sarcomere Z-line, thick filament, thin filament Actin, myosin, sliding filament

Profilin Interaction with Actin Filament Barbed End ... · Developmental Cell Article Profilin Interaction with Actin Filament Barbed End Controls Dynamic Instability, Capping, Branching,

Mechanical Properties of Actin Gels - Elastic Modulus and Filament Motions

Motor mechanisms II. Review questions Binding of ATP to myosin head causes: a) actin filament to slide b) Myosin head to detatch from actin filament

Structures of Actin-Binding Proteins - princeton.edu · Structures of Actin-Binding Proteins A new model for filament severing Schutt, C., Lindberg, U., Karlsson, R., Weeds A., Pope,

Myosin and actin filament lengths in diaphragms from ...muscle.ucsd.edu/More_HTML/papers/pdf/Poole_JAP_1994.pdf · Myosin and actin filament lengths in diaphragms from emphysematous

CASEIN KINASE1-LIKE PROTEIN2 Regulates Actin Filament ... · CASEIN KINASE1-LIKE PROTEIN2 Regulates Actin Filament Stability and Stomatal Closure via Phosphorylation of Actin Depolymerizing

Actin Filament Assembly, Growth, Branching, Capping and Disassembly are Controlled by Actin Binding Proteins

A 13-/ Map of the Actin-Scruin Filament from the Limulus

Orji nnamdi portfolio 2014 undergraduate

Actin stress fibers – assembly, dynamics and …assembly mechanisms of protrusive actin filament networks are relatively well understood, the molecular mechanisms underlying the

Cofilin reduces the mechanical properties of actin ...people.bu.edu/parkhs/Papers/kimPCCP2015.pdfAn actin filament is an essential cytoskeleton protein in a cell. Various proteins

Tropomyosin master regulator of actin filament function …jcs.biologists.org/content/joces/128/16/2965.full.pdf · Tropomyosin – master regulator of actin filament function in

Sliding Filament Theory - Default Store View · Web view• Thin filaments are made of these three protein molecules: 1. actin 2. tropomyosin 3. troponin Page 12. Actin • The major

Siwes Report CHISOM SAM ORJI

PRESENTED BY ORJI JONATHAN ORJI

Weebly · Web viewMyosin, thick with heads Actin, thin helix, binding sites Muscle contraction Z-lines get closer Sliding filament theory Interaction of actin and myosin depends on

ATP - University of UtahATP MYOSIN ACTIN FILAMENT ATP binds to MYOSIN MYOSIN releases ACTIN ATP hydrolizes MYOSIN binds new ACTIN Releasing phosphate group powers the cranking motion

Molecular Motors Filament…….motor Actin…….….myosins Tubulin….….dynein and kinesins

Contractile structure Sarcomere structure Contractile filament composition – Myosin (thick) – Actin (thin) Anchors and attachments – Z-disk – Titin/nebulin

Mechanistic principles underlying regulation of the actin ...signal transduction | molecular dynamics simulations Polymerization of actin filament networks against membranes provides

Archaeal actin from a hyperthermophile forms a single ...crenactin filament and its evolutionary relationship to F-actin. In both crystals (with two different space groups) crenactin

The Roles of Actin-Binding Domains 1 and 2 in the …...2015/10/01  · The Roles of Actin-Binding Domains 1 and 2 in the Calcium-Dependent Regulation of Actin Filament Bundling by

Actin Filament Assembly by Arp2-3 and Formins

Phosphomimetic S3D cofilin binds but only weakly severs actin … · actinfilamentlengthinthepresenceandabsenceofcofilin(Fig. 4A and Table 4). Little change in average actin filament

X-ray scattering study of actin polymerization nuclei ... · filament nucleators, such as Spire, Cobl, VopL, and VopF (Fig. 1A). The actin monomers bound to the individual W domains