Intermediate Filaments

Intermediate Filaments

Family of related proteins that function mainly in
strengthening of the cytoskeleton.

non-polar

Intermediate filaments are __________________.

molecular motors

Intermediate filaments do not support ______________________.

eye

Orphans are intermediate filaments found in the _________.

α-helical

Intermediate filaments have head and tail domains that determine the specific functions that are connected by central ______________ rod domain which plays central role in filament assembly.

ends

Intermediate filaments do not have distinct __________ (non-polar).

stable

Intermediate filaments are more ___________ and don’t have the dynamic behavior of actin filaments or microtubules.

Desmosomes

These are junctions between adjacent cells.

desmoplakin

The attachment of keratin filaments is mediated by ________________.

Hemidesmosomes

These are junctions between epithelial cells and underlying connective tissue.

plakins

Keratin filaments are linked to integrins by different _____________.

Plectin

__________ binds actin filaments and microtubules, forming bridges between them and between intermediate filaments.

Epidermolysis bullosa simplex

This is a condition characterized by very fragile skin; skin blisters from cell lysis.

KRT5; KRT14

EBS is caused by keratin gene mutations in ________ and
__________ keratin genes and PLEC gene that encodes
plectin.

Basal laminae

This is a thin matrix layer on which epithelial cells rest; surrounds muscle cells, adipose cells, and peripheral nerves

connective

Extracellular matrix is most abundant in ______________ tissues.

Tendon

These have a high proportion of fibrous proteins

Cartilage

These have a high level of polysaccharides that form a compression-resistant gel.

triple

Collagens form ____________ helices.

I

Type ____ Collagen is the most abundant type of collagen.

IV

Type ______ Collagen forms networks (basal lamine).

glycosaminoglycans

Extracellular matrix gels are formed from polysaccharides called ______________________ (GAGs); repeating units of
disaccharides.

negatively

The sulfate groups of GAGs makes them highly _________________ charged.

Hyaluronan

This is the only GAG that is a single long polysaccharide
chain.

proteoglycans

GAGs are linked to proteins to form __________________.

hylauronan

Proteoglycans interact with ___________ to form large complexes in the extracellular matrix.

Aggrecan

This is the major proteoglycan of cartilage.

Fibronectin

This is the main adhesion protein of connective tissues.

Nidogen

This is an adhesion protein that also binds to type IV collagen.

Integrins

These are transmembrane proteins that attach cells to the extracellular matrix.

Hemidesmosomes

These anchor epithelial cells to basal laminae.

Focal adhesions

This is a cell-matrix junction where bundles of actin filaments
are anchored to β subunits of integrins via other
proteins: α-actinin, talin, and vinculin.

reversibly

Integrins can ____________ bind matrix components, due to their ability to change conformation between active and inactive states.

Adherens junctions

These are cell-to-cell adhesion complexes that primarily function to hold adjacent cells together within a tissue, essentially acting as a "glue" that maintains tissue structure and integrity by linking cells through protein interactions.