Presentation is loading. Please wait.

Presentation is loading. Please wait.

Telomeres special sequences at chromosome ends special proteins protect them.

Similar presentations


Presentation on theme: "Telomeres special sequences at chromosome ends special proteins protect them."— Presentation transcript:

1 Telomeres special sequences at chromosome ends special proteins protect them

2 Telomeres special sequences at chromosome ends special proteins protect them can't copy 5' end of lagging strand since remove primer

3 Telomeres can't copy 5' end of lagging strand since remove primer telomeres lose ~ 200 bp/S

4 Telomeres can't copy 5' end of lagging strand since remove primer telomeres lose ~ 200 bp / S telomerase replaces them

5 Telomerase telomeres lose ~ 200 bp / S telomerase replaces them reverse transcriptase with attached RNA template

6 Telomerase telomeres lose ~ 200 bp each S telomerase replaces missing bases reverse transcriptase with attached RNA template 1) RNA bonds leading strand

7 Telomerase reverse transcriptase with attached RNA template 1) RNA bonds leading strand 2) Forms template to extend leading strand

8 Telomerase reverse transcriptase with attached RNA template 1) RNA bonds leading strand 2) Forms template to extend leading strand 3) Translocates 6 bases & repeats

9 Telomerase reverse transcriptase with attached RNA template 1) RNA bonds leading strand 2) Forms template to extend leading strand 3) Translocates 6 bases & repeats 4) Extend lagging strand with primer & DNA pol

10 Telomeres Aging theory:” mature” cells lose telomerase

11 Telomeres Aging theory:” mature” cells lose telomerase lose DNA each S

12 Telomeres Aging theory:” mature” cells lose telomerase lose DNA each S Die when lose too much

13 Telomeres Aging theory:” mature” cells lose telomerase lose DNA each S Die when lose too much Cancer cells reactivate telomerase

14 Telomeres Aging theory:” mature” cells lose telomerase lose DNA each cell cycle Die when lose too much Cancer cells reactivate telomerase [serum telomerase] can diagnose cancer

15 Telomeres Aging theory:” mature” cells lose telomerase lose DNA each S Die when lose too much Cancer cells reactivate telomerase [serum telomerase] can diagnose cancer Inhibiting telomerase kills cancer cells

16 Telomeres Aging theory:” mature” cells lose telomerase lose DNA each S Die when lose too much Cancer cells reactivate telomerase [serum telomerase] can diagnose cancer Inhibiting telomerase kills cancer cells Telomerase is symptom cf cause of cancer

17 Regulating E3 ligases The COP9 signalosome (CSN), a complex of 8 proteins, regulates E3 ligases by removing Nedd8 from cullin

18 Regulating E3 ligases The COP9 signalosome (CSN), a complex of 8 proteins, regulates E3 ligases by removing Nedd8 from cullin CAND1 then blocks cullin

19 Regulating E3 ligases The COP9 signalosome (CSN), a complex of 8 proteins, regulates E3 ligases by removing Nedd8 from cullin CAND1 then blocks cullin Ubc12 replaces Nedd8

20 Regulating E3 ligases The COP9 signalosome (CSN), a complex of 8 proteins, regulates E3 ligases by removing Nedd8 from cullin CAND1 then blocks cullin Ubc12 replaces Nedd8 Regulates DNA-damage response, cell-cycle & gene expression

21 Regulating E3 ligases The COP9 signalosome (CSN), a complex of 8 proteins, regulates E3 ligases by removing Nedd8 from cullin CAND1 then blocks cullin Ubc12 replaces Nedd8 Regulates DNA-damage response, cell-cycle & gene expression Not all E3 ligases associate with Cullins!

22 COP1 is a non-cullin-associated E3 ligase Protein degradation is important for light regulation COP1/SPA1 tags transcription factors for degradation W/O COP1 they act in dark In light COP1 is exported to cytoplasm so TF can act

23 COP1 is a non-cullin-associated E3 ligase Recent data indicates that COP1 may also associate with CUL4

24 Protein degradation rate varies 100x Most have motifs marking them for polyubiquitination : taken to proteosome & destroyed Other signals for selective degradation include PEST & KFERQ PEST : found in many rapidly degraded proteins e.g. ABCA1 (which exports cholesterol in association with apoA-I) is degraded by calpain

25 Protein degradation rate varies 100x Other signals for selective degradation include PEST & KFERQ PEST : found in many rapidly degraded proteins e.g. ABCA1 (which exports cholesterol in association with apoA-I) is degraded by calpain Deletion increases t 1/2 10x, adding PEST drops t 1/2 10x

26 Protein degradation rate varies 100x Other signals for selective degradation include PEST & KFERQ PEST : found in many rapidly degraded proteins e.g. ABCA1 (which exports cholesterol in association with apoA-I) is degraded by calpain Deletion increases t 1/2 10x, adding PEST drops t 1/2 10x Sometimes targets poly-Ub

27 Protein degradation rate varies 100x Other signals for selective degradation include PEST & KFERQ PEST : found in many rapidly degraded proteins e.g. ABCA1 (which exports cholesterol in association with apoA-I) is degraded by calpain Deletion increases t 1/2 10x, adding PEST drops t 1/2 10x Sometimes targets poly-Ub Recent yeast study doesn’t support general role

28 Protein degradation rate varies 100x Other signals for selective degradation include PEST & KFERQ PEST : found in many rapidly degraded proteins e.g. ABCA1 (which exports cholesterol in association with apoA-I) is degraded by calpain Deletion increases t 1/2 10x, adding PEST drops t 1/2 10x Sometimes targets poly-Ub Recent yeast study doesn’t support general role KFERQ: cytosolic proteins with KFERQ are selectively taken up by lysosomes in chaperone-mediated autophagy under conditions of nutritional or oxidative stress.


Download ppt "Telomeres special sequences at chromosome ends special proteins protect them."

Similar presentations


Ads by Google