Archipelago/ hCdc4

By: Joe Pietropaoli

Review: Ubiquitylation

E1 – ubiquitin-activating enzyme

E2 – ubiquitin-conjugating enzyme

E3 – ubiquitin-protein ligase

www.myoops.org/.../0/chp_ub_p_sys.jpg

CDC 4

*Specific type of E3 ligase F-box Protein 7 WD40 protein-binding motifs

Rajagopalan et al. Fig. 1-a

CDC 4 as E3 Ligase

Ariizumi et al. Fig. 2

CDC 4 First Discovered in Budding Yeast

Pintard et al. Fig. 1

CDC 4 Homologues

Drosophila: Archipelago (Ago)

Mammals: Cdc 4 (humans = hcdc 4)

Both target cyclin E in respective organisms

Ago in Drosophila

Development Growth

(Wild-type embryos stained (in vivo evidence of with Ago Specific Anti Serum) association with dmyc)

Moberg et al. Fig. 5-aMortimer et al. Fig. 1

CDC 4 in Mammals

Knockout Mouse Experiment: homozygous mutant mice (cdc4-/-)

-Subjects dies at about 10 days of Embryogenesis

-Mice suffered from intracranial hemorrhaging

-Mice did not show variation of cyclin E, and maintained cyclin E controlled Cdk2 activity

http://dailyscreenshots.de/screenshot/mike-tysons-punch-out/nes-1873781

Keiko et al.

CDC 4 in Mammals

Knockout mouse Experiment (cont)

heterozygous mutant mice (cdc4+/-)

-viable; greater susceptibility to radiation induced tumorogenisis

-most tumors maintained and expresses wt cdc4 allele

-cdc4 = haploinsufficient tumor suppressor gene

CDC 4 in Mammals cont.

In vitro trial knocking out hcdc 4 in human cell lines

Rajagopalan et al. Fig. 2-a

Results:hCDC4-/- cells proved to be chromosomally unstable

Situation Summary: Mutation and loss of function in hcdc4 does not allow the SCF molecule to assemble

and associate with cyclin E. Resulting over expression of cyclin E causes CI.

Rajagopalan et al. Fig. 3

Endometrial Cancer

-Cancer of the Uterine Wall

-Caused be somatic mutations followed by LOH of the wild-type allele

-Consistent with Knudson’s two hit hypothesis of tumor suppressor genes.

-No evidence of hereditary cases

-Highly Curable

http://www.instablogsimages.com/images/2007/09/13/alcohol-may-bump-risk-of-cancer-of-womb_9.jpg

Connecting hCDC4 and Endometrial Cancer

a Two of these tumors also contained phos-cyclin E.

Tumor grade (G3/G2) hCDC4 gene mutation

Cyclin E protein (8) 7/1 3/8a

Phos-cyclin E (7) 6/1 6/7

Neither (38) 16/22 1/15

Spruck et al. Table 2

Connecting hCDC4 to Endometrial Cancer

No. Mutation Codona Result LOH 4q32

6 GAG    TAT 124 Glu    Tyr +

7 AAA    (TC)A (2-bp insertion) 371 Lys    Ser, term codon 376 +

8 CGA    TGA 367 Arg    Ter +

9 CGT    CAT 465 Arg    His nib

10 CGA    CAA 479 Arg    Gln +

11 CGA    TGA 658 Arg    Ter +

12 AGA    A(A)G (1-bp insertion) 472 Arg    Lys, term codon 476 +

14 GTT    ATT 23c Val    Ile +

Spruck et al. Table 3

Endometrial Cancer: Diagnosis

Risk Factors

taking tamoxifen

taking estrogen alone

Diagnosis

first detected by a pelvic screen

confirmed by endometrial biopsy

Standard Treatments

Surgery

Chemotherapy

Radiation Therapy

Hormone Therapy

Clinical Trial

Study ShowsIn advanced endometrial cancer,

chemotherapy is better than whole-abdominal radiation

Chemotherapy comes after an initial operation

Chemotherapy is a combination of drugs: doxorubicin (adriamycin®) and cysplatin (platinol®)