Retina International's Scientific Newsletter

	Retina International's Scientific Newsletter
Editor's Notes from literature on Rab Escort Protein (REP)

Recent update from: 19.12.1999

REP1, CHM

Notes

RFLPs with probe pZ11 (DXS540)
Probe has two EcoRI fragments (pZ11a: 1.2 + pZ11b: 4.2 kb) and one EcoRI/Sau3A fragment (pZ11c: 1.6 kb)
pZ11a single copy, pZ11b repetitive element
EcoRV RFLP of pZ11a: 7.3 (53%) + 5.3 kb (47%) PIC: 0.62
MspI RFLP of pZ11a: 7.5 (69%) + 16.5 kb (31%) PIC: 0.45
EcoRI RFLP of pZ11c: 4.5 (64%) + 4.2 kb (36%) PIC: 0.62

Species: Homo sapiens

See also:

Chromosomal localisation	in man: Xq21.2
	in mouse:

Gene Data

Exons:

Primers:

Protein Data

Aminoacids:

Molecularweight	on SDS-PAGE:
	calculated:

Reference: (12)

REP1, CHM

Notes

geranylgeranylates Rab-Proteins (small GTP binding proteins)
Two components: REP1 = component A, catalytic = component B
Geranylgeranyl = 20 carbon isoprenoid
CHM lymphoblast show 25% of normal activity for GGtase
USH2 lymphoblasts show normal activity
CHM therories:
1. retina specific Rab for REP1
2. large requirements for multiple Rabs deplete REP1 activity
3. block by special unprenylated Rab
4. deficient geranylation of a non-Rab

Species: Homo sapiens

See also:

Chromosomal localisation	in man:
	in mouse:

Gene Data

mRNA: 5.4 kb

Exons:

Primers:

Protein Data

Aminoacids: 395 AA

Molecularweight	on SDS-PAGE: 95 kDa
	calculated:

Reference: (17)

REP1, CHM

Notes

Species: Homo sapiens

See also:

Chromosomal localisation	in man:
	in mouse:

Gene Data

Exons: 15

Primers: Complete

Protein Data

Aminoacids:

Molecularweight	on SDS-PAGE:
	calculated:

Reference: (20)

REP1, CHM

Notes

Indispensable stimulation of geranylation
REP activity before and after geranylation
Completed structure
150 kb genomic DNA
X-chromosomal breakpoint of X;7 translocation between exons 3 and 4
Average intron size 10 kb
Still lacking 5' sequences
Evaluated splice sites
Possibly 1 exon preceeding exon 1 due to splice acceptor at a position where homology to mCHM suddenly stops
Unusual repeat near splice donor of exon 9: (AT)4-12C with 20 - 40 repeats

Species: Homo sapiens

See also:

Chromosomal localisation	in man: Xq21.2
	in mouse:

Gene Data

mRNA: 5.6 kb

Exons: 15

Primers:

Protein Data

Aminoacids: 653 AA

Molecularweight	on SDS-PAGE:
	calculated:

Reference: (21)

REP1, CHM

Notes

REP1 specific for Ram/Rab27
Purification scheme for Rab27
Unknown function

Species: Homo sapiens

See also:

Chromosomal localisation	in man:
	in mouse:

Gene Data

Exons:

Primers:

Protein Data

Aminoacids:

Molecularweight	on SDS-PAGE:
	calculated:

Reference: (14)

REP1, CHM

Notes

Geranylates Rab3A (2 isoprenoids) and Rab1A (1 isoprenoid)
CXC, CC C-terminal sequence required as target
Rab1A bound to ER
Copurifies in the early isolation steps with component B as a complex of 350 kDa
Component B elutes on a high salt column as 100 kDa complex, component A as 120 kDa protein

Species: Homo sapiens

See also:

Chromosomal localisation	in man:
	in mouse:

Gene Data

Exons:

Primers:

Protein Data

Aminoacids:

Molecularweight	on SDS-PAGE: 95 kDa
	calculated:

Reference: (18)

REP1, CHM

Notes

Differences to Cremer's REP1: 1. 287 bp 5' are different, 2. 295T-G = TAA-GAA = ter - Gln
Diffrence 2 augments the protein by 49 AA
Patient analysis: 8/34 had no CHM-mRNA though positive Southern, 17/34 had reduced mRNA levels
4 isolated CHM patients with normal amounts of REP1 mRNA
PEST sequence at AA 301-351

Species: Homo sapiens

See also:

Chromosomal localisation	in man: Xq21.1-21.2
	in mouse:

Gene Data

cDNA:

Exons:

Primers:

Protein Data

Aminoacids: 365 AA

Molecularweight	on SDS-PAGE:
	calculated: 42000

Reference: (11)

REP1, CHM

Notes

Repeat in intron 14 (CA)19
5 Alleles: 151 - 153 - 155 - 157 - 161 bp PCR-product (2% - 51% - 37% - 9% - 1%), PIC: 0.67

Species: Homo sapiens

See also:

Chromosomal localisation	in man:
	in mouse:

Gene Data

Exons:

Primers: CHM-CA14

Protein Data

Aminoacids:

Molecularweight	on SDS-PAGE:
	calculated:

Reference: (22)

REP1, CHM

Notes

ORF = 948 bp = 316 AA
Linked marker loci: DXS95, DXS165, DXS233
No polyadenylation signal
Potential phosphorylation sites for PRKC (residues 76, 122, 175, 178, 301)
No other posttranslational modifikation sites
2 PEST regions
PEST site determines intracellular half lifes of less than 2h
Minimum 60 kb of genomic DNA

Species: Homo sapiens

See also:

Chromosomal localisation	in man: Xq21
	in mouse:

Gene Data

Exons: 9

Primers:

Protein Data

Aminoacids:

Molecularweight	on SDS-PAGE:
	calculated:

Reference: (8)

REP1, CHM

Notes

Dinucleotide-binding glycine-rich loop (P-loop) preceeded by a b-strand of bulky, hydrophobic residues
Conserved feature of REPs and GDIs
Feature like a FAD-binding domain, difference: last Gly is Gln in REP and GDI
Function remains unclear

Species: Homo sapiens

See also:

Chromosomal localisation	in man:
	in mouse:

Gene Data

Exons:

Primers:

Protein Data

Aminoacids:

Molecularweight	on SDS-PAGE:
	calculated:

Reference: (10)

REP1, CHM

Notes

Linked Marker: DXS165(p1bD5), DXS72(px65H7), DXYS1(pdp34), DXS56 (pL2.98)
Deletion detected with probe p1bD5

Species: Homo sapiens

See also:

Chromosomal localisation	in man: Xq21.1-21.33
	in mouse:

Gene Data

Exons: 9

Primers:

Protein Data

Aminoacids:

Molecularweight	on SDS-PAGE:
	calculated:

Reference: (7)

REP1, CHM

Notes

Complete deletion of REP1
Two branches of clinical pictures:
A: severe with extensive areas of chorioretinal degeneration in the midperiphery and periphery, marked thinning of retinal vessels and scattert pigment clumps
constriction of visual fields to 5 , visual acuity 0.7/0.9 (20/30//20/20)
Carrier A: slightly pathologic fundus,
B: late: less-developed chorioretinal degeneration of the midperiphery
early: minimal degenerative changes like a carrier

Species: Homo sapiens

See also:

Chromosomal localisation	in man:
	in mouse:

Gene Data

Exons:

Primers:

Protein Data

Aminoacids:

Molecularweight	on SDS-PAGE:
	calculated:

Reference: (13)

REP1, CHM

Notes

Preparative FIGE of a 635 kb SfiI-fragment detected with marker DXS165
FIGE conditions

Species: Homo sapiens

See also:

Chromosomal localisation	in man: Xq21.2
	in mouse:

Gene Data

Exons:

Primers:

Protein Data

Aminoacids:

Molecularweight	on SDS-PAGE:
	calculated:

Reference: (24)

REP1, CHM

Notes

79 additional AA at 5' with clone p642

Species: Homo sapiens

See also:

Chromosomal localisation	in man: Xq21.1-21.33
	in mouse:

Gene Data

Exons:

Primers:

Protein Data

Aminoacids:

Molecularweight	on SDS-PAGE:
	calculated:

Reference: (9)

REP1, CHM

Notes

Mutation disrupts mCHM gene by insertion of neo^r gene
heterozygous females have neither affected males nor affected carrier offspring
Mutation was detected in blastocysts
Mutation is lethal only with maternal origin in carriers
Preferential inactivation of paternal X-chromosome in murine extraembryonic membranes
Photoreceptor degeneration in heterozygous and chimeras
Differences between REP/GGtase system or Rab substrates in man and mouse

Species: Mus musculus

See also:

Chromosomal localisation	in man:
	in mouse:

Gene Data

Exons:

Primers:

Protein Data

Aminoacids:

Molecularweight	on SDS-PAGE:
	calculated:

Reference: (25)

REP1, CHM

Notes

INL, IPL, GCL normal
Present photoreceptors were normal in length
Striking b-wave reduction in chimeras, no reduction in heterozygotes
Negative a-wave, positive deflection b-wave
Histology: ONLwas reduced, border of OPL-ONL irregular, RPE was intact and filled with pigment granula, choroid was normal except for melanocytes between the capillaries

Species: Mus musculus

See also:

Chromosomal localisation	in man:
	in mouse:

Gene Data

Exons:

Primers:

Protein Data

Aminoacids:

Molecularweight	on SDS-PAGE:
	calculated:

Reference: (25)

REP2, CHMl

Notes

ORF = 1968 bp
Regions of homology to smg p25A GDI
Mouse CHMl is unpublished
AA 260 - 655 are 73% identical to mCHM and 76% hCHM
Originates possibly through reverse transcription from CHM

Species: Homo sapiens

See also:

Chromosomal localisation	in man: 1q31-qter
	in mouse:

Gene Data

Exons: 1

Primers:

Protein Data

Aminoacids: 656 AA

Molecularweight	on SDS-PAGE:
	calculated:

Reference: (9)

REP, REP1

Notes

Rab1a single Cys mutations accepting only 1 geranylation
Only REP (not Ggtase) forms a stable complex with the unprenylated, mono- and di-GG Rab
REP-mono-GG-Rab1a is stable even in the presence of detergents or phospholipids
mono-GG-Rab does not accumulate
REP-di-GG-complex dissociates under the above conditions
Prenylation induces change in complex stoichiometry
Each geranylgeranyl attachment is indepndent from the other
Prenylation of Rab1a is dependend on and stoichiometric with REP concentration
Rab GGtase action is not stoichiometric
Digeranylation involves a lipid-resistant transitional complex

Species:

See also:

Chromosomal localisation	in man:
	in mouse:

Gene Data

Exons:

Primers:

Protein Data

Aminoacids:

Molecularweight	on SDS-PAGE:
	calculated:

Reference: (19)

REP, REP1

Notes

Binds GDP-bound Rab
Nearly all Rabs are prenylated by REP2

Species:

See also: GDI

Chromosomal localisation	in man:
	in mouse:

Gene Data

Exons:

Primers:

Protein Data

Aminoacids:

Molecularweight	on SDS-PAGE:
	calculated:

Reference: (26)

REP, REP1

Notes

Strict preference for GDP-bound Rab

Species:

See also:

Chromosomal localisation	in man:
	in mouse:

Gene Data

Exons:

Primers:

Protein Data

Aminoacids:

Molecularweight	on SDS-PAGE:
	calculated:

Reference: (15)

REP1, REP1

Notes

25% European patients with Deletions
40% of the mutant alleles contain point mutations
1/3 European patients no mutations found
Subset of Rab need REP1 for prenylation
Rab 27 eye specific target in rats
Small Rab27 proportion is still membrane asociated (low prenylation by REP2)-effect
Incomplete prenylation of Rab27 accounts for the time dependence of disease onset and variations in phenotype

Species: Homo sapiens

See also: Rab27

Chromosomal localisation	in man: Xq21
	in mouse:

Gene Data

Exons:

Primers:

Protein Data

Aminoacids:

Molecularweight	on SDS-PAGE:
	calculated:

Reference: (16)

REP1, REP1

Notes

No necessity of a cellular factor to release Rab from REP after geranylation
Rab-GDP is converted to Rab GTP by GEF
Binds modified and unmodified Rab5 but mediates only membrane association of modified Rab
Membrane-binding is temperature and time dependent
REP1 removes Rab2, 5, and 7 from membranes
Does not require ATP
Rab exchange from REP to membrane does not require GDI
REP binds preferentially GDP-Rab

Species: Homo sapiens

See also:

Chromosomal localisation	in man:
	in mouse:

Gene Data

Exons:

Primers:

Protein Data

Aminoacids:

Molecularweight	on SDS-PAGE:
	calculated:

Reference: (1)

REP1, REP1

Notes

Inactivation stuidesin a lymphoblastoid cell line with t(X,13) translocation revealed not X-inactivation of REP1

Species: Homo sapiens

See also:

Chromosomal localisation	in man:
	in mouse:

Gene Data

Exons:

Primers:

Protein Data

Aminoacids:

Molecularweight	on SDS-PAGE:
	calculated:

Reference: (5)

REP1, REP1

Notes

Higher affinity for GDP-bound form of Rab7
Affinity for GDP and GDP form should be sufficient for the formation of stable complexes
Affinity diffrences arise from differences in the dissociation rates
ATCC clone: 62334
Kd for GDP is 1nM
Kd for GTP is 20 nM
Prenylated Rab should act much more strongly with REP1 than unprenylated

Species: Rattus norvegicus

See also: Rab7

Chromosomal localisation	in man:
	in mouse:

Gene Data

Exons:

Primers:

Protein Data

Aminoacids:

Molecularweight	on SDS-PAGE:
	calculated:

Reference: (2)

REP1, REP1

Notes

REP1 and 2 mediates Rab1A, 5A, 6
25% reduced activity for REP2 on Rab 3A, B, and D
Rab5A required for membrane fusion and early endosomes
Rab6 required in intra-golgi vesicular transport
REP1 is released on transfer of Rab to acceptor protein which inserts Rab to the membrane
REP1 retina specific
REP2 supplements REP1 in non-retinal cells
Rab1A predominantly in ER
Rab3A component of neuronal synaptic vesicles

Species: Recombinant

See also:

Chromosomal localisation	in man:
	in mouse:

Gene Data

Exons:

Primers: Rab3A, Rab3D, REP1 cDNA

Protein Data

Aminoacids:

Molecularweight	on SDS-PAGE: 95 kDa
	calculated:

Reference: (6)

REP1, REP2

Notes

Marker D1S58
No involvement of REP2 in 19 USH2 patients
87% identity to CHM protein
No introns
ORF-PCR varies between 249 to 334 bp due to identities with REP1 sequence
Silent 438A-G substitution resulting in Ser 146 Ser

Species: Homo sapiens

See also:

Chromosomal localisation	in man: 1q42-qter
	in mouse:

Gene Data

Exons: 1

Primers: Complete + 3 CHM specific

Protein Data

Aminoacids:

Molecularweight	on SDS-PAGE:
	calculated:

Reference: (23)

REP, REP2

Notes

Species: Mus musculus

See also:

Chromosomal localisation	in man:
	in mouse: 1

Gene Data

Exons:

Primers:

Protein Data

Aminoacids:

Molecularweight	on SDS-PAGE:
	calculated:

Reference: (4)

REP1, type 1

Notes

Resembles Rab3A-GDI
Binds unprenylated Rab1A
Presents Rab to GGtase component B
Stays to Rab after geranylation
Recycling of REP1 by transferring Rab to Rab-acceptor like GDI
Rab family directs membrane flow
Rab GGtase does not bind to the C-terminus of its substrate
3'UTR of 2.5 kb
Identity: rat-mouse 91% over 592 AA, rat-CHM 87% over 395 AA, rat-CHMl 70% over 650 AA
X-chromosomal localization
GGtase transfers 2 geranyl-groups to Rab

Species: Rattus norvegicus

See also: Rab

Chromosomal localisation	in man:
	in mouse:

Gene Data

Exons:

Primers:

Protein Data

Aminoacids: 650 AA

Molecularweight	on SDS-PAGE: 95 kDa
	calculated:

Reference: (3)

References:

1. Alexandrov, K., Horiuchi, H., Steele Mortimer, O., Seabra, M.C., and Zerial, M. Rab escort protein-1 is a multifunctional protein that accompanies newly prenylated rab proteins to their target membranes. 1994; EMBO J. 13: 5262 - 5273.
Goto Top Link to PudMed

2. Alexandrov, K., Simon, I., Iakovenko, A., Holz, B., Goody, R.S., and Scheidig, A.J. Moderate discrimination of REP-1 between Rab7 x GDP and Rab7 x GTP arises from a difference of an order of magnitude in dissociation rates. 1998; FEBS Lett. 425: 460 - 464.
Goto Top Link to PudMed

3. Andres, D.A., Seabra, M.C., Brown, M.S., Armstrong, S.A., Smeland, T.E., Cremers, F.P., and Goldstein, J.L. cDNA cloning of component A of Rab geranylgeranyl transferase and demonstration of its role as a Rab escort protein. 1993; Cell. 73: 1091 - 1099.
Goto Top

4. Barrat, F.J., Depetris, D., Certain, S., Mattei, M.G., and de Saint Basile, G. Localization of the Rab escort protein-2 (REP2) and inositol 1,4, 5-trisphosphate 3-kinase (ITPKB) genes to mouse chromosome 1 by in situ hybridization and precision of the syntenic regions between mouse and human 1q42-q44. 1997; Genomics. 43: 111 - 113.
Goto Top

5. Carrel, L. and Willard, H.F. The X-linked choroideremia gene escapes X- chromosome inactivation. 1993; Am.J.Hum.Genet. 53: Abst. 42
Goto Top

6. Cremers, F.P., Armstrong, S.A., Seabra, M.C., Brown, M.S., and Goldstein, J.L. REP-2, a Rab escort protein encoded by the choroideremia-like gene. 1994; J.Biol.Chem. 269: 2111 - 2117.
Goto Top

7. Cremers, F.P., Brunsmann, F., van de Pol, T.J., Pawlowitzki, I.H., Paulsen, K., Wieringa, B., and Ropers, H.H. Deletion of the DXS165 locus in patients with classical choroideremia. 1987; Clin.Genet. 32: 421 - 423.
Goto Top

8. Cremers, F.P., van de Pol, D.J., van Kerkhoff, L.P., Wieringa, B., and Ropers, H.H. Cloning of a gene that is rearranged in patients with choroideremia. 1990; Nature. 347: 674 - 677.
Goto Top Link to PudMed

9. Cremers, F.P.M., Molloy, C.M., van de Pol, D.J.R., van den Hurk, J.A.J.M., Bach, I., van Kessel, A.H.M.G., Ropers, H.H., Cremers, F.P., van de Pol, D.J., van den Hurk, J.A., and Geurts van Kessel, A.H. An autosomal homologue of the choroideremia gene colocalizes with the Usher syndrome type II locus on the distal part of chromosome 1q. 1992; Hum.Mol.Genet. 1: 71 - 75.
Goto Top Link to PudMed

10. Koonin, E.V. Human choroideremia protein contains a FAD-binding domain [letter]. 1996; Nat.Gen. 12: 237 - 239.
Goto Top

11. Merry, D.E., Janne, P.A., Landers, J.E., Lewis, R.A., and Nussbaum, R.L. Isolation of a candidate gene for choroideremia. 1992; Proc.Natl.Acad.Sci.U.S.A. 89: 2135 - 2139.
Goto Top

12. Molloy, C.M., van de Pol, T.J., Brohet, R.M., Ropers, H.H., and Cremers, F.P. Three RFLPs for pZ11 (DXS540) in the choroideremia gene at Xq21.2. 1992; Nucleic.Acids.Res. 20: 1434
Goto Top

13. Ponjavic, V., Abrahamson, M., Andreasson, S., Van Bokhoven, H., Cremers, F.P., Ehinger, B., and Fex, G. Phenotype variations within a choroideremia family lacking the entire CHM gene. 1995; Ophthalmic Genet. 16: 143 - 150.
Goto Top Link to PudMed

14. Seabra, M.C. The pathogenesis of choroideremia: identification of a REP 1 specific Rab. 1995; Invest.Ophthalmol.Vis.Sci. 36: S893
Goto Top

15. Seabra, M.C. Nucleotide dependence of Rab geranylgeranylation. Rab escort protein interacts preferentially with GDP-bound Rab. 1996; J.Biol.Chem. 271: 14398 - 14404.
Goto Top

16. Seabra, M.C. New insights into the pathogenesis of choroideremia: a tale of two REPs [editorial; comment]. 1996; Ophthalmic Genet. 17: 43 - 46.
Goto Top

17. Seabra, M.C., Brown, M.S., and Goldstein, J.L. Retinal degeneration in choroideremia: deficiency of rab geranylgeranyl transferase. 1993; Science. 259: 377 - 381.
Goto Top

18. Seabra, M.C., Brown, M.S., Slaughter, C.A., Sudhof, T.C., and Goldstein, J.L. Purification of component A of Rab geranylgeranyl transferase: possible identity with the choroideremia gene product. 1992; Cell. 70: 1049 - 1057.
Goto Top Link to PudMed

19. Shen, F. and Seabra, M.C. Mechanism of digeranylgeranylation of Rab proteins. Formation of a complex between monogeranylgeranyl-Rab and Rab escort protein. 1996; J.Biol.Chem. 271: 3692 - 3698.
Goto Top

20. Van Bokhoven, H., Schwartz, M., Andreasson, S., van den Hurk, J.A., Bogerd, L., Jay, M., Ruther, K., Jay, B., Pawlowitzki, I.H., Sankila, E.M., and et al. Mutation spectrum in the CHM gene of Danish and Swedish choroideremia patients. 1994; Hum.Mol.Genet. 3: 1047 - 1051.
Goto Top Link to PudMed

21. Van Bokhoven, H., van den Hurk, J.A., Bogerd, L., Philippe, C., Gilgenkrantz, S., de Jong, P., Ropers, H.H., and Cremers, F.P. Cloning and characterization of the human choroideremia gene. 1994; Hum.Mol.Genet. 3: 1041 - 1046.
Goto Top Link to PudMed

22. Van Bokhoven, H., van Genderen, C., Ropers, H.H., and Cremers, F.P. Dinucleotide repeat polymorphism within the choroideremia gene at Xq21.2. 1994; Hum.Mol.Genet. 3: 1446
Goto Top Link to PudMed

23. Van Bokhoven, H., von Genderen, C., Molloy, C.M., van de Pol, D.J., Cremers, C.W., von Aarem, A., Schwartz, M., Rosenberg, T., Geurts van Kessel, A.H., Ropers, H.H., and et al. Mapping of the choroideremia-like (CHML) gene at 1q42-qter and mutation analysis in patients with Usher syndrome type II. 1994; Genomics. 19: 385 - 387.
Goto Top

24. van de Pol, T.J., Cremers, F.P., Brohet, R.M., Wieringa, B., and Ropers, H.H. Derivation of clones from the choroideremia locus by preparative field inversion gel electrophoresis. 1990; Nucleic.Acids.Res. 18: 725 - 731.
Goto Top

25. van den Hurk, J.A., Hendriks, W., van de Pol, D.J., Oerlemans, F., Jaissle, G., Ruther, K., Kohler, K., Hartmann, J., Zrenner, E., Van Bokhoven, H., Wieringa, B., Ropers, H.H., and Cremers, F.P. Mouse choroideremia gene mutation causes photoreceptor cell degeneration and is not transmitted through the female germline. 1997; Hum.Mol.Genet. 6: 851 - 858.
Goto Top Link to PudMed

26. Wu, S.K., Zeng, K., Wilson, I.A., and Balch, W.E. Structural insights into the function of the Rab GDI superfamily. 1996; Trends.Biochem.Sci. 21: 472 - 476.
Goto Top Link to PudMed

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Contact the editor: irpamp@irpa.org	This site is maintained and edited by Dr. rer. medic. Markus Preising, Dipl.Biol. Molecular Genetics Laboratory Department of Paediatric Ophthalmology, Strabismology and Ophthalmogenetics University of Regensburg Head: Prof. Dr. med. Birgit Lorenz