Intermediate Filaments Flashcards
IF general structure
8 tetramers in 1 ropelike filament, many lateral contacts, subunit assembly doesn’t require ATP or GTP
IF Organisation
Nuc to Cell membrane across cytoplasm linking cells together and to ECM. No polarity so no motor function.
IF location and role
Role: tensile strength, stretch resistence
Anchoring junctions (desmo and hemides)
Cytoplasmic: Keratins (epi) Vimentin and Vim related (CT, M cells, neuroglia) Neurofilaments
Nuclear: Nuc lamina
Describe Keratin IFs
If defective allows disconnect of epi layer from basal lamina
Desmin: M IF
Mechanical stress, protective network around each myofibril at Z-disk
GFAP
Astrocyte Mechanical strength
Lamins
Inner surface of nuc envelope for struc stability of nucleus protecting DNA, anchor for chroms, TFs, nuclear pores
Neurofilaments
Axons, NF crosslinking long axon.
NF: tensile str
MT: transport
Role of IFs in Detection of Cancer Origin
Tumor cells lose normal appearance but can tell origin by IF expression. Fluorescent antibodies used to determine origin = epi, mesenchymal, neuronal tissue
Metastasis detection
Describe Bullosa simplex
Rupture of Keratin IFs connected to Basal Lamina. AD, Keratin 5/14, blisters on BM, fragile skin - minor friction/trauma = blisters
Describe Hyperkeratosis
Mut in keratin 1/10, supra basilar differentiation of keratinocytes
Defect weakens structural stability of keratinocytes leading to easy blisters
Chronic wounds = hyperproliferation = thick skin
Describe Plantopalmer Keratoderma
K9 defect = only in thick skin