1. The Biology of Keratins or why are they so important? Birgit Lane birgit@cmm.a-star.edu.sg CRUK Cell Structure Research Group, University of Dundee and Centre for Molecular Medicine, Singapore

4. immunofluorescence “ We live our whole lives less than 1/10mm away from certain death “ W. Montagna

5. ToughTough WaterproofWaterproof DisposableDisposable Self-healingSelf-healing Site of most cancersSite of most cancers Skin - the ultimate barrier tissue K5/K14 K1/K10 EPIDERMIS DERMIS

6. Scratch wound assays movie: Sharon Jenner

7. Keratins as Intermediate filament proteins Cytoskeleton filaments Many family members Major structural components of sheet tissues Different proteins in different body parts Many diseases (40+)

8. The Intermediate Filament Gene Family Type Ikeratinsepithelia Type IIkeratinsepithelia 54 Type IIIvimentin-likemesenchyme Type IVneurofilamentsneurones Type Vlaminsall nuclei Type VI(variable) ______________________________ Total70 }

9. Structure of intermediate filaments after Herrmann and Aebi

10. monomer dimer tetramer unit length filament 10 nm filament immature filament

11. stratified (barrier) simple Basal cells Transparent: cornea Wet: mucosal Thin dry: cornified (skin) Stress: fast turnover, wound response K9- thick dry: palmoplantar skin Simple: internal, secretory, embryonic Type IIType I K2e K9 K2p K10 K12 K3 K18 K8 K19 K14 K5 K15 K13 K4 K7 K20 K16 K6a K17 K6b K1b K1 basal Keratin filament proteins

12. K5/K14 K1/K10 EPIDERMIS DERMIS

13. Epidermolysis bullosa simplex

14. stratified (barrier) simple Basal cells Transparent: cornea Wet: mucosal Thin dry: cornified (skin) Stress: fast turnover, wound response K9- thick dry: palmoplantar skin Simple: internal, secretory, embryonic Type IIType I K2e K9 K2p K10 K12 K3 K18 K8 K19 K14 K5 K15 K13 K4 K7 K20 K16 K6a K17 K6b K1b K1 basal Keratin filament proteins

15. Bullous congenital ichthyosiform erythroderma (BCIE, EHK) Thickened skin Fragile suprabasal cells Mutations in K1 or K10 Mostly rod end hotspots

16. stratified (barrier) simple Basal cells Transparent: cornea Wet: mucosal Thin dry: cornified (skin) Stress: fast turnover, wound response K9- thick dry: palmoplantar skin Simple: internal, secretory, embryonic Type IIType I K2e K9 K2p K10 K12 K3 K18 K8 K19 K14 K5 K15 K13 K4 K7 K20 K16 K6a K17 K6b K1b K1 basal Keratin filament proteins

17. Fragility late in differentiation K2e, K1 mutations Mostly rod end hotspots Ichthyosis bullosa of Siemens (IBS)

18. None K5/K14 K1/K10 K2e Effects of keratin mutations on cell integrity EBS BCIE (EHK) IBS

19. stratified (barrier) simple Basal cells Transparent: cornea Wet: mucosal Thin dry: cornified (skin) Stress: fast turnover, wound response K9- thick dry: palmoplantar skin Simple: internal, secretory, embryonic Type IIType I K2e K9 K2p K10 K12 K3 K18 K8 K19 K14 K5 K15 K13 K4 K7 K20 K16 K6a K17 K6b K1b K1 basal Keratin filament proteins

20. Pachyonychia congenita - Type 1 (K6a, K16) - Type 2 (K6b, K17)

21. K6a/K16, K6b/K17 - the stress response keratins K6a, K16 - PC-1 K6b, K17 - PC-2 major keratins in “wet” skin surfaces; outer hair follicle sheath; nail bed. NOT normally in thin “dry”skin but more in thick skin INDUCED by trauma, wounding Often expressed in tissue cultured cells Small amounts in “wet” epithelia. Lots in deep hair follicle sheath; some basal cells; nail bed. Specialized and unspecialized cells. NOT normally in thin “dry” skin. INDUCED by trauma, wounding, inflammation Often expressed in tissue cultured cells

22. K16 induced by epidermal wounding Healing blister: Keratinocytes downregulate K10 and express K6/K16/K17 upon stress or injury. + - K16

23. epidermis Outer hair follicle: lots of K16, very little K17 Deep hair follicle: lots of K17, very little K16

24. Disorders caused by defective intermediate filaments (at least 40 disorders so far) http://www.interfil.org