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®)