Ras-related protein Rab-1B (RAB1B)

The protein contains 201 amino acids for an estimated molecular weight of 22171 Da.

 

The small GTPases Rab are key regulators of intracellular membrane trafficking, from the formation of transport vesicles to their fusion with membranes (PubMed:20545908, PubMed:9437002). Rabs cycle between an inactive GDP-bound form and an active GTP-bound form that is able to recruit to membranes different set of downstream effectors directly responsible for vesicle formation, movement, tethering and fusion (PubMed:9437002). Plays a role in the initial events of the autophagic vacuole development which take place at specialized regions of the endoplasmic reticulum (PubMed:20545908). Regulates vesicular transport between the endoplasmic reticulum and successive Golgi compartments (By similarity). Promotes the recruitment of lipid phosphatase MTMR6 to the endoplasmic reticulum-Golgi intermediate compartment (By similarity). (updated: June 2, 2021)

Protein identification was indicated in the following studies:

  1. Goodman and co-workers. (2013) The proteomics and interactomics of human erythrocytes. Exp Biol Med (Maywood) 238(5), 509-518.
  2. Lange and co-workers. (2014) Annotating N termini for the human proteome project: N termini and Nα-acetylation status differentiate stable cleaved protein species from degradation remnants in the human erythrocyte proteome. J Proteome Res. 13(4), 2028-2044.
  3. Hegedűs and co-workers. (2015) Inconsistencies in the red blood cell membrane proteome analysis: generation of a database for research and diagnostic applications. Database (Oxford) 1-8.
  4. Wilson and co-workers. (2016) Comparison of the Proteome of Adult and Cord Erythroid Cells, and Changes in the Proteome Following Reticulocyte Maturation. Mol Cell Proteomics. 15(6), 1938-1946.
  5. Bryk and co-workers. (2017) Quantitative Analysis of Human Red Blood Cell Proteome. J Proteome Res. 16(8), 2752-2761.
  6. D'Alessandro and co-workers. (2017) Red blood cell proteomics update: is there more to discover? Blood Transfus. 15(2), 182-187.
  7. Chu and co-workers. (2018) Quantitative mass spectrometry of human reticulocytes reveal proteome-wide modifications during maturation. Br J Haematol. 180(1), 118-133.

Methods

The following articles were analysed to gather the proteome content of erythrocytes.

The gene or protein list provided in the studies were processed using the ID mapping API of Uniprot in September 2018. The number of proteins identified and mapped without ambiguity in these studies is indicated below.
Only Swiss-Prot entries (reviewed) were considered for protein evidence assignation.

PublicationIdentification 1Uniprot mapping 2Not mapped /
Obsolete
TrEMBLSwiss-Prot
Goodman (2013)2289 (gene list)227853205992269
Lange (2014)123412347281224
Hegedus (2015)2638262202352387
Wilson (2016)165815281702911068
d'Alessandro (2017)18261817201815
Bryk (2017)20902060101081942
Chu (2018)18531804553621387

1 as available in the article and/or in supplementary material
2 uniprot mapping returns all protein isoforms as one entry

The compilation of older studies can be retrieved from the Red Blood Cell Collection database.

The data and differentiation stages presented below come from the proteomic study and analysis performed by our partners of the GReX consortium, more details are available in their published work.

No sequence conservation computed yet.

Interpro domains
Total structural coverage: 100%
Model score: 50

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The reference OMIM entry for this protein is 612565

Ras-associated protein rab1b; rab1b

DESCRIPTION

Members of the RAB protein family, such as RAB1B, are low molecular mass monomeric GTPases localized on the cytoplasmic surfaces of distinct membrane-bound organelles. RAB1B functions in the early secretory pathway and is essential for vesicle transport between the endoplasmic reticulum (ER) and Golgi (Chen et al., 1997; Alvarez et al., 2003).

CLONING

By PCR using degenerate primers based on conserved sequences in human RAB transcripts, Chen et al. (1997) obtained a partial RAB1B cDNA from a pigmented human melanoma cell cDNA library. The deduced 53-amino acid stretch spans GTP-binding domains II and III and has only 1 or 2 amino acid changes from the homologous stretch in rat Rab1b and human RAB1A (179508), respectively. RAB1B appeared to be a low-abundance transcript in the human melanoma cells. By searching databases for RAS family members, followed by PCR, He et al. (2002) cloned RAB1B. The deduced 201-amino acid RAB1B protein contains 4 highly conserved GTPase motifs and a C-terminal geranylgeranylation motif. Northern blot analysis detected strong expression of a major transcript of about 2.4 kb in all tissues examined.

GENE FUNCTION

Alvarez et al. (2003) found that expression of the RAB1B asn121-to-ile (N121I) mutant, which is impaired in guanine nucleotide binding, blocked forward transport of vesicles from the Golgi to the ER and induced Golgi disruption in HeLa cells. The N121I mutant caused a phenotype analogous to that induced by brefeldin A (BFA): it caused resident Golgi proteins to relocate to the ER, and it induced redistribution of the ER-Golgi intermediate compartment proteins ERGIC53 (LMAN1; 601567), GM130 (GOLGA2; 602580), and p115 (603344) to punctate structures. N121I caused dissociation of beta-COP (COPB; 600959) from membranes, implicating RAB1B in a pathway leading to the recruitment of the coatomer complex (COPI; 601924). The N121I phenotype was rescued by expression of ARF1 (103180) and GBF1 (603698), which mediate COPI recruitment. Like expression of ARF1 and GBF1, expression of a constitutively active RAB1B gln67-to-leu (Q67L) mutant prevented Golgi fragmentation and beta-COP dissociation in BFA-treated cells. Alvarez et al. (2003) concluded that RAB1B has a role in the GBF1/ARF1-mediated pathway for COPI recruitment. Monetta et al. (2007) found that the GTP-bound form of human RAB1B enhanced membrane association of GBF1 and COPI at ER exit sites (ERES). RAB1B also modulated ARF1-induced membrane association and dissociation at the Golgi. Through an N-terminal domain, RAB1B-GTP, but not RAB1B-GDP, interacted directly with GBF1, and RAB1B was required for GBF1 membrane association at Golgi structures. In RAB1B-depleted HeLa cells, GBF1 and beta-COP redistributed from the juxtanuclear region to a diffuse, cytosolic pattern. RAB1B also colocalized with COPII (see 610511)/ERES, with transport-associated vesicular tubular clusters, and with COPI structures. Monetta et al. (2007) proposed that RAB1B-GTP induces GBF1 recruitment at the ERES interface and at the Golgi complex, where it is required for COPII/COPI exchange or COPI vesicle formation, respectively. By mixing the Legionella pneumophila effector protein DrrA with RAB1B and ATP, Mueller et al. (2010) found that the N-terminal domain of DrrA transferred AMP to (i.e., AMPylated) tyr77 in the switch II region of RAB1B, but not other RAB proteins. DrrA-mediated AMPylation was required for the Legionella effector pro ... More on the omim web site

Subscribe to this protein entry history

July 1, 2021: Protein entry updated
Automatic update: Entry updated from uniprot information.

Feb. 22, 2019: Protein entry updated
Automatic update: Entry updated from uniprot information.

Feb. 2, 2018: Protein entry updated
Automatic update: Uniprot description updated

Dec. 19, 2017: Protein entry updated
Automatic update: Uniprot description updated

June 20, 2017: Protein entry updated
Automatic update: comparative model was added.

March 16, 2016: Protein entry updated
Automatic update: OMIM entry 612565 was added.

Jan. 28, 2016: Protein entry updated
Automatic update: model status changed

Jan. 25, 2016: Protein entry updated
Automatic update: model status changed