240 18 pt 1. Intermediate Filaments

cytoskeleton

gives the cell its shape, allows the cell to organize its components, produces large-scale movements (muscle cxn, cell movement)

microtubules, actin, intermediate

the cytoskeleton is made of networks of 3 different filaments: list them

dynamic

the cytoskeleton is _______. This property of the cytoskeleton makes sense for the efficiency of assembly & disassembly of parts as necessary, rather than relying on large proteins

phosphorylation/dephosphorylation

the cytoskeleton is made of dynamic polymers. how would a cell regulate polymer dynamics? __________/___________

reversibly, non covalently

do the subunits of polymers associate non reversibly or reversibly? do subunits of cytoskeleton polymers interact covalently or non covalently?

intermediate

_________ filaments are the strongest, most stable elements of the cytoskeleton

intermediate

the cell needs help withstanding mechanical stress applied to it & withstand tensile strength. what filament primarily helps with this?

no

are intermediate filaments found in plants & fungi?

plectin

proteins like _____ link intermediate filaments to other structures in the cell- forming a scaffold

deformed/damaged

mutation in intermediate filaments would most likely result in what kind of cell phenotype?

cytoplasm

intermediate filaments are either specific to the cytoplasm or the nucleus. keratins, vimetin, and neurofilaments are found in the _______

epithelia

where are intermediate filaments “keratins” found specifically?

connective tissue, muscles

where are the intermediate filaments “vimentin” found specifically?

nerve cells

where are the intermediate filaments “neurofilaments” found?

animal cells

where are the intermediate filaments “nuclear lamins” found?

alpha helix, N, C

the intermediate filament monomer consists of a ______ rod, and an amino terminal domain at the ____ term, and carboxy terminal domain at the ____ term

no

Can intermediate filaments bind nucelotides?

polar, unpolar

coiled-coil dimers are _______ (polar/unpolar), while tetramer of two coiled-coil dimers is ______ (polar/unpolar)

2, 4

a tetramer is made of ___ dimers, _____ monomers

32

8 tetramers = a growing filament, which is ____ monomers

T

T/F a tetramer is non polar; symmetric

cellular factors

intermediate filament tail domains can extend from the filament and cross link them, or bind

conserved, crosslinking

in intermediate filaments, the central rod/coiled coil domain is _______, but flanking N & C terminal regions can mediate _____

metastatic

in cancer cells, tissue expression of Intermediate filament proteins is used for determining if cancer is ______ or not

keratins

_________ are intermediate filaments expressed in epithelial cells

desmosomes

the sites of cell-cell interaction at which keratins are attached to the membrane are called __________, which aid in mechanical durability

lateral

in addition to mechanical stress, keratins provide tissues w/ protection against _____ shear forces

keratin

in a mutant, mechanical forces induce splitting of epithelial cell layers, leading to the formation of skin blisters. what is mutated?

nuclear membrane

nuclear lamins form a tough network of filaments within the nucleus, just underneath the _________ _________

chromosomes, interphase

lamins also provide an attachment site for ________ during _______ (which phase), and likely contribute to gene expression

depolymerized, dephosphorylated

nuclear lamins are dissassembled via ____________ during mitosis, causing the nuclear envelope to break down, enabling access to _______ during mitosis

lamin

mutation in _____ genes results in altered gene expression

phosphorylated, dephospohroylated

nuclear lamins are induced to disassemble when ________ during mitosis, and induced to assemble when ________

no

do intermediate filaments have motor proteins?