RAB27A Research Articles

Griscelli syndrome-type 2 in twin siblings: case report and update on RAB27A human mutations and gene structure

Griscelli syndrome (GS) is a rare autosomal recessive disorder caused by mutation in the MYO5A (GS1, Elejalde), RAB27A (GS2) or MLPH (GS3) genes. Typical features of all three subtypes of this disease include pigmentary dilution of the hair and skin and silvery-gray hair. Whereas the GS3 phenotype is restricted to the pigmentation dysfunction, GS1 patients also show primary neurological impairment and GS2 patients have severe immunological deficiencies that lead to recurrent infections and hemophagocytic syndrome. We report here the diagnosis of GS2 in 3-year-old twin siblings, with silvery-gray hair, immunodeficiency, hepatosplenomegaly and secondary severe neurological symptoms that culminated in multiple organ failure and death. Light microscopy examination of the hair showed large, irregular clumps of pigments characteristic of GS. A homozygous nonsense mutation, C-T transition (c.550C>T), in the coding region of the RAB27A gene, which leads to a premature stop codon and prediction of a truncated protein (R184X), was found. In patient mononuclear cells, RAB27A mRNA levels were the same as in cells from the parents, but no protein was detected. In addition to the case report, we also present an updated summary on the exon/intron organization of the human RAB27A gene, a literature review of GS2 cases, and a complete list of the human mutations currently reported in this gene. Finally, we propose a flow chart to guide the early diagnosis of the GS subtypes and Chédiak-Higashi syndrome.

Muscle cells engage Rab8A and myosin Vb in insulin-dependent GLUT4 translocation

Insulin causes translocation of glucose transporter 4 (GLUT4) to the membrane of muscle and fat cells, a process requiring Akt activation. Two Rab-GTPase-activating proteins (Rab-GAP), AS160 and TBC1D1, were identified as Akt substrates. AS160 phosphorylation is required for insulin-stimulated GLUT4 translocation, but the participation of TBC1D1 on muscle cell GLUT4 is unknown. Moreover, there is controversy as to the AS160/TBC1D1 target Rabs in fat and muscle cells, and Rab effectors are unknown. Here we examined the effect of knockdown of AS160, TBC1D1, and Rabs 8A, 8B, 10, and 14 (in vitro substrates of AS160 and TBC1D1 Rab-GAP activities) on insulin-induced GLUT4 translocation in L6 muscle cells. Silencing AS160 or TBC1D1 increased surface GLUT4 in unstimulated cells but did not prevent insulin-induced GLUT4 translocation. Knockdown of Rab8A and Rab14, but not of Rab8B or Rab10, inhibited insulin-induced GLUT4 translocation. Furthermore, silencing Rab8A or Rab14 but not Rab8B or Rab10 restored the basal-state intracellular retention of GLUT4 impaired by AS160 or TBC1D1 knockdown. Lastly, overexpression of a fragment of myosin Vb, a recently identified Rab8A-interacting protein, inhibited insulin-induced GLUT4 translocation and altered the subcellular distribution of GTP-loaded Rab8A. These results support a model whereby AS160, Rab8A, and myosin Vb are required for insulin-induced GLUT4 translocation in muscle cells, potentially as part of a linear signaling cascade.

Griscelli Syndrome Type 2: A Rare and Lethal Disorder

Griscelli syndrome is a rare autosomal recessive disorder. It is characterized by pigment dilution and variable immune deficiency leading to increased susceptibility to certain infections and a tendency to develop a life-threatening hemophagocytic syndrome known as the accelerated phase. Griscelli syndrome is now classified into 3 types based on the genetic and molecular features. Primary neurological presentation without the accelerated phase is rare in type 2. In this article, the authors report a boy who was presented with seizures and diffuse white matter involvement unaccompanied by the other features of the accelerated phase. Mutation analysis in family members revealed the presence of a missense mutation in Rab27a gene. In addition to the rare presentation, this is the first case of Griscelli syndrome to be reported from Jordan.

Microphthalmia-associated Transcription Factor Regulates RAB27A Gene Expression and Controls Melanosome Transport

Melanosomes are lysosome-related organelles specialized in melanin synthesis and transport. In this study, we show that microphthalmia-associated transcription factor (MITF) silencing induces melanosome gathering around the nucleus and causes the relocalization of Rab27A, Slac2a-Mlph, and Myo5a that control the transport of melanosomes on the actin network. In an attempt to elucidate the mechanism by which MITF controls melanosome distribution, we identify RAB27A as a new MITF target gene. Indeed, MITF silencing leads to a dramatic decrease in Rab27A expression and blocks the stimulation of Rab27A expression evoked by cAMP. Further, forced expression of MITF increases Rab27A expression, indicating that MITF is required and sufficient for Rab27A expression in melanoma cells. MITF binds to two E-boxes in the proximal region of the Rab27A promoter and stimulates its transcriptional activity. Finally, re-expression of Rab27A, in MITF-depleted cells, restores the transport of melanosomes to the cell periphery. These results show that RAB27A is a new direct transcriptional target of MITF and link MITF to melanosome transport, another key parameter of melanocyte differentiation and skin pigmentation. Interestingly, Rab27A is involved in other fundamental physiological functions, such as the transport of lytic granules and insulin secretion. Thus our results, deciphering the mechanism of Rab27A transcriptional regulation, have an interest that goes beyond the skin pigmentation field.

A further Turkish case of Griscelli syndrome with new RAB27A mutation

To the Editor: Griscelli syndrome (GS) is a rare autosomal recessive disorder characterized by partial albinism, hepatosplenomegaly, variable cellular immune deficiency, and hemophagocytic lymphohistiocytosis.1 Similar features have been described in two other syndromes, Chédiak-Higashi syndrome and Elejalde syndrome. Differential diagnosis of these syndromes is given in Table I. Approximately 50 cases with GS have been reported up date.2 GS is caused by a defect in either the RAB27A or MYO5A gene.

A novel missense mutation (G43S) in the switch I region of Rab27A causing Griscelli syndrome

The autosomal recessive Griscelli syndrome type II (GSII) is caused by mutations in the RAB27A gene. Typical clinical features include immunological impairment, silver-gray scalp hair, eyelashes and eyebrows and hypomelanosis of the skin. Rabs help determine the specificity of membrane trafficking steps within cells. In melanocytes, the GTP-bound form of Rab27A associates with the membranes of mature fully-pigmented melanosomes through its geranylgeranyl group. Once attached, Rab27A recruits the downstream effector Melanophilin (Mlph) and the actin-dependent motor protein Myosin Va (MyoVa). The molecular Rab27A/Mlph/MyoVA tripartite complex, which links melanosomes to the peripheral actin network, is required to achieve melanosome transfer to surrounding keratinocytes in the epidermis. Here we report a novel homozygous missense mutation c.127G>A, p.G43S in exon 2 of the RAB27A gene of an Afghani GSII patient. Laser scanning confocal microscopy showed that the G43S mutation, which is located in the highly conserved switch I region of Rab27A, induces perinuclear localization of melanosomes in normal melanocytes, and fails to restore melanosomes to the actin-rich periphery in GSII melanocytes. Co-immunoprecipitation studies showed that Rab27A(G43S) fails to interact with its effector Melanophilin, indicating that the switch I region functions in the recruitment of Rab effector proteins.

S2050 Prostanglandin E2 Receptors Are Involved in Nicotine-Induced Gastric Tumor Growth

We have previously determined that the small GTPase Rab25 regulates membrane recycling in epithelial cells. However, little is known whether membrane recycling and vesicle trafficking pathways influence epithelial tissue transformation and neoplasia. Based on the hypothesis that membrane recycling is necessary to maintain epithelial cell polarity, we sought to determine the effects of Rab25 loss on the development of colonic neoplasia. We therefore bred Rab25 knockout mice in the C57BL/6 background onto the ApcMin/+ mouse. To understand the function of Rab25, we have developed a mouse model for deletion of the Rab25 gene product. To assess the effects of Rab25 loss on the development of colonic neoplasia, we have bred Rab25 knockout mice on the C57BL/6 background onto the ApcMin/ +mouse. At 4months of age, Rab25-/-ApcMin/+mice showed 175 intestinal polyps compared with 45.4 in Rab25+/+ApcMin/+ mice and 98.5 in Rab25+/-ApcMin/+ mice (p<0.01). In the colon, Rab25-/-ApcMin/+ 4.7 colon tumors compared with only 1.9 in Rab25+/+ApcMin/ + mice (p<0.01) and 3.5 in Rab25+/-ApcMin/+ mice. Histopathological analysis of the polyps in Rab25-/-ApcMin/+ mice showed diffuse and fused microadenomas with high mitotic index compared to control. We also sought to examine Rab25 gene expression in a large panel of colon cancer tumor isolates by mining a previously characterized series of mouse and human tumor gene microarray expression profile data. Expression of Rab25 was significantly decreased in colon adenocarcinomas (p<0.03) independent of Duke's stage. In addition, Kaplan-Meier analysis demonstrated that lower expression of Rab25 correlated with significantly lower survival (p<0.035). These results show that the loss of Rab25 promotes the initiation of intestinal polyposis inmice and reductions in Rab25 correlate with poor prognosis in human colorectal cancer. These findings indicate that aberrations in vesicle trafficking may promote intestinal neoplasia.

Analysis of RAB27A Gene in Griscelli Syndrome type 2: Novel Mutations Including a Deletion Hotspot

Griscelli syndrome type 2 is an autosomal recessive disorder characterized by pigmentary dilution and occurrence of acute phases of hemophagocytosis. The disease is caused by mutations in RAB27A gene, coding a small GTPase involved in terminal phases of cytotoxic granule/melanosome exocytosis. We describe the result of mutation analysis among nine patients from seven non-related Persian families. We present four novel mutations including a deletion hot spot (514del 5). This hot spot is flanked by "direct repeats" of nucleotides, which are previously shown to be associated with areas of recurrent small deletions.

Rab10 in insulin-stimulated GLUT4 translocation

In fat and muscle cells, insulin stimulates the movement to and fusion of intracellular vesicles containing GLUT4 with the plasma membrane, a process referred to as GLUT4 translocation. Previous studies have indicated that Akt [also known as PKB (protein kinase B)] phosphorylation of AS160, a GAP (GTPase-activating protein) for Rabs, is required for GLUT4 translocation. The results suggest that this phosphorylation suppresses the GAP activity and leads to the elevation of the GTP form of one or more Rabs required for GLUT4 translocation. Based on their presence in GLUT4 vesicles and activity as AS160 GAP substrates, Rabs 8A, 8B, 10 and 14 are candidate Rabs. Here, we provide further evidence that Rab10 participates in GLUT4 translocation in 3T3-L1 adipocytes. Among Rabs 8A, 8B, 10 and 14, only the knockdown of Rab10 inhibited GLUT4 translocation. In addition, we describe the subcellular distribution of Rab10 and estimate the fraction of Rab10 in the active GTP form in vivo. Approx. 5% of the total Rab10 was present in GLUT4 vesicles isolated from the low-density microsomes. In both the basal and the insulin state, 90% of the total Rab10 was in the inactive GDP state. Thus, if insulin increases the GTP form of Rab10, the increase is limited to a small portion of the total Rab10. Finally, we report that the Rab10 mutant considered to be constitutively active (Rab10 Q68L) is a substrate for the AS160 GAP domain and, hence, cannot be used to deduce rigorously the function of Rab10 in its GTP form.

Rab23 GTPase is expressed asymmetrically in Hensen's node and plays a role in the dorsoventral patterning of the chick neural tube

The mouse Rab23 protein, a Ras-like GTPase, inhibits signaling through the Sonic hedgehog pathway and thus exerts a role in the dorsoventral patterning of the spinal cord. Rab23 mouse mutant embryos lack dorsal spinal cord cell types. We cloned the chicken Rab23 gene and studied its expression in the developing nervous system. Chick Rab23 mRNA is initially expressed in the entire neural tube but retracts to the dorsal alar plate. Unlike in mouse, we find Rab23 in chick already expressed asymmetrically during gastrulation. Ectopic expression of Rab23 in ventral midbrain induced dorsal genes (Pax3, Pax7) ectopically and reduced ventral genes (Nkx2.2 and Nkx6) without influencing cell proliferation or neurogenesis. Thus, in the developing brain of chick embryos Rab23 acts in the same manner as described for the caudal spinal cord in mouse. These data indicate that Rab23 plays an important role in patterning the dorso-ventral axis by dorsalizing the neural tube.

NK cytotoxicity mediated by CD16 but not by NKp30 is functional in Griscelli syndrome

AbstractGriscelli syndrome (GS) type 2 is an autosomal recessive disorder represented by pigment dilution and impaired cytotoxic T lymphocyte (CTL) activity. NK activity has been scarcely investigated in GS patients. Here, we describe a new patient, possessing a hemophagocytic syndrome with a homozygous Q118X nonsense RAB27A mutation. Single specific primer–polymerase chain reaction (SSP-PCR) was developed based on this mutation and is currently used in prenatal genetic analysis. As expected, CTLs in the patient are not functional and NK cytotoxicity against K562 or 721.221 cells is diminished. Surprisingly, however, we demonstrate that CD16-mediated killing is intact in this patient and is therefore RAB27A independent, whereas NKp30-mediated killing is impaired and is therefore RAB27A dependent. We further analyzed the signaling pathways of these 2 receptors and demonstrated phosphorylation of Vav1 after CD16 activation but not after NKp30 engagement. Thus, we identify a novel homozygous mutation in the RAB27A gene of a new GS patient, observe for the first time that some activating NK receptors function in GS patients, and demonstrate a functional dichotomy in the killing mediated by these human NK-activating receptors.

Oral 2, Silver hair in a 3-year-old child

A 32‐month‐old girl of Pakistani origin presented to the paediatricians with a short history of abdominal pain, decreased appetite and lethargy and a history of developmental delay. She was referred to us when it was noted that her hair and eyebrows were silver in colour. While in hospital, she became progressively more unwell, developed neck stiffness and refused to walk. A diagnosis of acute meningitis was made and a prelumbar puncture computed tomographic scan showed hydrocephalus with enlarged third and lateral ventricles. She underwent a third ventriculostomy and insertion of a reservoir. Magnetic resonance imaging showed multiple focal ill‐defined enhancement with larger enhancing masses in the cerebellum. These appearances were initially thought suggestive of widely disseminated lymphoma or leukaemia. Surgical biopsy of these lesions was performed and histology showed some evidence of histiocytic tumour with a degree of erythrophagocytosis and lymphophagocytosis. In view of the histology and the phenotypic features, Griscelli syndrome was considered. Blood and hair from the patient were analysed and she was confirmed to be homozygous for a mutation in the RAB27A gene, which has been described in Griscelli syndrome. She has subsequently undergone bone marrow transplantation. Griscelli syndrome is a rare autosomal recessive disorder resulting in partial albinism and a combined immunodeficiency.1 Our case is unusual in that the presentation was neurological with no evidence of cytopenia. 1 Mancini AJ, Chan LS, Paller AS. Partial albinism with immunodeficiency: Griscelli syndrome: report of a case and review of the literature. J Am Acad Dermatol 1998; 38:295–300.

The Slc35d3 gene, encoding an orphan nucleotide sugar transporter, regulates platelet-dense granules

AbstractPlatelet dense granules are lysosome-related organelles which contain high concentrations of several biologically important low-molecular-weight molecules. These include calcium, serotonin, adenine nucleotides, pyrophosphate, and polyphosphate, which are necessary for normal blood hemostasis. The synthesis of dense granules and other lysosome-related organelles is defective in inherited diseases such as Hermansky-Pudlak syndrome (HPS) and Chediak-Higashi syndrome (CHS). HPS and CHS mutations in 8 human and at least 16 murine genes have been identified. Previous studies produced contradictory findings for the function of the murine ashen (Rab27a) gene in platelet-dense granules. We have used a positional cloning approach with one line of ashen mutants to establish that a new mutation in a second gene, Slc35d3, on mouse chromosome 10 is the basis of this discrepancy. The platelet-dense granule defect is rescued in BAC transgenic mice containing the normal Slc35d3 gene. Thus, Slc35d3, an orphan member of a nucleotide sugar transporter family, specifically regulates the contents of platelet-dense granules. Unlike HPS or CHS genes, it has no apparent effect on other lysosome-related organelles such as melanosomes or lysosomes. The ash-Roswell mouse mutant is an appropriate model for human congenital-isolated delta-storage pool deficiency.

Rab23 is a potential biological target for treating hepatocellular carcinoma

To elucidate the role of Rab23 in hepatocellular carcinoma (HCC) by assessing the expression of Rab23 in HCC tissue and in HCC cell lines. Primary tumors (n = 100) were stained with Rab23 antibodies using immunohistochemistry and in situ hybridization in tissue microarrays. Relationships between gene expression and pathology parameters were analysed. The biological significance of Rab23 in Hep-3B cells was examined by knocking down Rab23 gene expression. We designed a pair of double-stranded RNAs against human rab23 and transfected siRNA into Hep-3B cells. Rab23 expression in these cells was examined using RT-PCR and Western blots. We investigated cell growth by MTT assays and fluorescence-activated cell sorting. High cytoplasmic and nuclear expression of Rab23 was found in 38 of 71 (53.5%) and in 49 of 68 HCC patients (72%) respectively, which correlated with tumor size. HCC cell lines expressed Rab23. In Hep3B cells, siRNA for Rab23 decreased Rab23 mRNA by 4.5-fold and protein expression by 2-fold. Survival rates at 24 and 48 h for Hep-3B cells transfected with siRNA were lower and about 30% Hep-3B cells were apoptotic. Knocking down rab23 suppressed Hep3B cell growth, suggesting that rab23 could play an important role in Hep3B cell growth. Rab23 is overexpressed and/or activated in HCC. Rab23 may be both a HCC predictor and a target for treating HCC.

Rabs 8A and 14 are targets of the insulin-regulated Rab-GAP AS160 regulating GLUT4 traffic in muscle cells

Insulin causes translocation of glucose transporter GLUT4 to the membrane of muscle and fat cells, a process requiring Akt activation. The Rab GTPase-activating protein (Rab-GAP) AS160 is inhibited upon phosphorylation by insulin-activated Akt, thereby allowing GLUT4 translocation. Although several Rab proteins are detected on GLUT4 vesicles, the target Rabs of AS160 involved in the GLUT4 translocation have not been identified. We test whether Rabs 8A, 10, and 14 ( in vitro targets of AS160) rescue the inhibition of GLUT4 translocation caused by ‘constitutively active’ 4P-AS160 in L6 muscle cells. Coexpression of GFP-tagged Rabs 8A or Rab14 with 4P-AS160 prevented the inhibition of GLUT4 translocation imposed by 4P-AS160. GFP-tagged, constitutively active Rab8A also elicited this rescue. In contrast, neither wild-type nor constitutively active GFP-tagged Rab10 restored GLUT4 translocation. These results suggest that Rab8A and possibly Rab14 may be targets of AS160 leading to GLUT4 translocation in L6 muscle cells.

Knockdown of Rab25 expression by RNAi inhibits growth of human epithelial ovarian cancer cells in vitro and in vivo

Ovarian cancer is the leading cause of cancer death among gynaecological malignancies. Elevated expression of Rab25 has been seen in this malignancy. To better understand its role in maintaining the malignant phenotype, we used RNA interference (RNAi) directed against Rab25 in our study. RNAi provides a new, reliable method to investigate gene function and has the potential for gene therapy. The aim of the study was to examine the anti-tumour effects elicited by a decrease in the level of Rab25 by RNAi and its possible mechanism of action. According to the Rab25 mRNA sequence in Genbank, a pair of 64 nt oligonucleotides were designed and synthesised, each containing the sites of restriction endonuclease at both ends. Oligonucleotides were annealed and ligated with linearised pSUPER by ligase. The recombinants (named pSUPER/Rab25 siRNA) were finally sequenced and identified by enzyme cutting and sequencing. The human ovarian cell line A2780 was grown without transfection, transfection with empty vector and with pSUPER/Rab25 siRNA with electroporation. The inhibitory effect was examined by RT-PCR, MTT, FCM and tumour growth of athymic nude mice. Rab25 siRNA expression vector was successfully constructed and identified by double endonuclease digestion. Sequence analysis of inserted fragment revealed the same sequence as synthesised siRNA oligonucleotides. Cells transfected with Rab25 siRNA can specifically knock down the transcription of Rab25, exhibiting cells with slower proliferation, increased apoptosis, and decreased tumour growth. Rab25 siRNA expression vector has been successfully constructed, and it could inhibit the tumour growth both in vitro and in vivo. Our data suggest that the Rab25 signalling pathway plays a role in the regulation of cell proliferation and apoptosis in ovarian cancer cells, which indicates that the Rab25 gene plays a definite role in the development and aggressiveness of human ovarian cancer and should be further elucidated as a possible therapeutic target of ovarian cancer.

Neurological presentation of Griscelli syndrome: Obstructive hydrocephalus without haematological abnormalities or organomegaly

Griscelli syndrome is a rare autosomal-recessive disorder characterised by partial albinism, immunodeficiency, organomegaly and accelerated phases. During accelerated phases, pancytopenia, haemophagocytosis, hypoproteinemeia occur which may be accompanied by neurological deterioration. Primary neurological presentation is rare and we report a case that presented with obstructive hydrocephalus and infiltrative lesions in the brain unaccompanied by other features of accelerated phase. Biopsy of these lesions demonstrated sinus histiocytosis. Electron microscopy of hair shaft and genetic studies established the diagnosis of Griscelli disease with RAB 27A mutation.

Involvement of Myosin Vb in Glutamate Receptor Trafficking

Myosin V motors mediate cargo transport; however, the identity of neuronal molecules transported by these proteins remains unknown. Here we show that myosin Vb is expressed in several neuronal populations and associates with the alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate-type glutamate receptor subunit GluR1. In developing hippocampal neurons, expression of the tail domain of myosin Vb, but not myosin Va, enhanced GluR1 accumulation in the soma and reduced its surface expression. These changes were accompanied by reduced GluR1 clustering and diminished frequency of excitatory but not inhibitory synaptic currents. Similar effects were observed upon expression of full-length myosin Vb lacking a C-terminal region required for binding to the small GTPase Rab11. In contrast, mutant myosin Vb did not change the localization of several other neurotransmitter receptors, including the glutamate receptor subunit NR1. These results reveal a novel mechanism for the transport of a specific glutamate receptor subunit in neurons mediated by a member of the myosin V family.

GRISCELLI SYNDROME: Description of a Case with Rab27A Mutation

A 7-month-old Turkish boy presented with partial albinism and typical clinical features of an accelerated phase, suggesting the diagnosis of Griscelli syndrome. The diagnosis was confirmed by light microscopic evaluation of hair and a peripheral blood smear. Genetic analysis identified a mutation in the Rab27A gene. He was initiated immunosuppressive treatment but accelerated phase could not be ameliorated. He unfortunately died from multiorgan failure. The finding of partial albinism in children should alert clinicians to consider Griscelli syndrome since simple methods can corfirm the diagnosis and early diagnosis is life-saving.

2 GLOBAL PEPTIDE SEQUENCING AND QUANTIFICATION OF PROTEINS IN PORCINE PARTHENOTES BY PROTEOMICS

Mass spectrometry (MS) is a powerful emerging tool in proteomics for global identification and quantification of proteins and their differential analysis. The aim of this study was to utilize MS for global peptide sequencing and the relative quantification of peptide sequences in porcine embryos produced by parthenogenesis. Oocytes (n = 6000) recovered from abattoir-derived prepubertal porcine ovaries were matured in vitro for 42–44 h and parthenogenetically activated by a single electric pulse of 1.36 kV cm-1. After 24 h of in vitro culture in NCSU23 medium supplemented with 0.4% BSA, presumptive zygotes were sampled in Laemmli buffer and stored in liquid nitrogen until analysis. SDS-PAGE was used as the first step to separate intact proteins into 16 fractions. Each fraction was then in-gel tryptic-digested and analyzed by nanoLC-nano-ESI-MS/MS to sequence the peptide components in each fraction by LTQ ion-trap mass spectrometer (Finnigan, Fresno, CA, USA) after peptide purification by C18 ZipTips (Millipore, Billerica, MA, USA). Synthetic peptides from Myoglobin (LFTGHPETL*EK) and MAP3 Kinase (IPTGTV*HNQAK) protein having an isotope-labeled carbon (*) were used as internal standards for relative quantification. In total, 54 060 peptides were sequenced. Of these, 259 proteins were identified in the NCBI protein database for Sus scrofa using Spectrum Mill software (Agilent Technologies, Palo Alto, CA, USA). Of these, 199 proteins were identified with high confidence having at least 2 peptide sequences matching each protein. These included heat shock protein families, ribosomal proteins, cytoskeletal proteins, mitochondrial enzymes, disulfide isomerase proteins, glutathione S-transferase, DNA methyltransferase, STAT1, Ras-related protein Rab 1A, voltage-dependent ion channel proteins, zinc finger proteins and elongation factors, etc., which are involved in several important metabolic and cell signaling pathways. Several proteins including DNA methyltransferase 1, peroxidoxin 2, ubiquitin carboxyl-terminal hydrolase L1, serpin, heat shock proteins, cytoskeletal proteins, mitochondrial enzymes, elongation factor 1, bone morphogenetic protein, glucose-related proteins, etc., were among the highly abundant proteins. Our results thus showed that proteomic strategy can be successfully applied to analyze porcine embryo proteome. To our knowledge, this is the first time that several proteins have been sequenced and quantified in porcine parthenotes by proteomic means. In the long run, this study may help the understanding of mechanisms underlying embryonic development and identification of biomarkers of embryo quality. This work was supported by grants from the Research Project on the Production of Bio-organs (No. 200503030202), Ministry of Agriculture and Forestry, and Korea Health 21 R&amp;amp;D Project (No. A060769), Ministry of Health and Welfare, Republic of Korea.