Affinage

DRC8

Dynein regulatory complex protein 8 · UniProt Q5VUJ9

Length
269 aa
Mass
29.7 kDa
Annotated
2026-06-09
11 papers in source corpus 2 papers cited in narrative 2 extracted findings
Cross-family judge vs UniProt: UniProt preferred faithfulness: 2/2 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

EFCAB2 (DRC8) is a calcium-binding protein defined by two EF-hand motifs that binds Ca2+ in vitro and is expressed exclusively in mouse testis, where it localizes specifically to the principal piece of the sperm flagellum (PMID:30933994). Independent loss-of-function work assigns it a role in osteoblast biology, as siRNA knockdown in MC3T3-E1 cells reduces osteoblast differentiation markers, indicating EFCAB2 promotes differentiation (PMID:29459627). Beyond its Ca2+-binding capacity and these two cellular contexts, the molecular mechanism, binding partners, and pathway placement of EFCAB2 have not been characterized in the available corpus.

Mechanistic history

Synthesis pass · year-by-year structured walk · 2 steps
  1. 2018 Medium

    Whether EFCAB2 has any cellular function was unknown; knockdown established a role in promoting osteoblast differentiation.

    Evidence siRNA knockdown in mouse MC3T3-E1 osteoblastic cells with ALP, mineralization, and marker readouts validated by qPCR

    PMID:29459627

    Open questions at the time
    • single lab, single loss-of-function method without rescue
    • no molecular mechanism or pathway linking EFCAB2 to differentiation
    • no identified binding partners or downstream effectors
  2. 2019 Medium

    The biochemical identity and tissue context of EFCAB2 were undefined; characterization established it as a testis-specific Ca2+-binding protein localized to the sperm flagellum principal piece.

    Evidence Northern/western blot, in situ hybridization, immunohistochemistry, structural modeling, and in vitro Ca2+-binding assays with recombinant protein in mouse

    PMID:30933994

    Open questions at the time
    • no functional genetic validation of a role in sperm or flagellar function
    • Ca2+-binding partners and effector pathway in the flagellum unknown
    • relationship between testis localization and the osteoblast phenotype unexplained

Open questions

Synthesis pass · forward-looking unresolved questions
  • How EFCAB2 Ca2+ binding is mechanistically coupled to flagellar function and to osteoblast differentiation, and whether these reflect a single shared molecular activity, remains unresolved.
  • no direct binding partners identified
  • no in vivo genetic model of sperm phenotype
  • no pathway placement for either context

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Localization
GO:0005929 cilium 1

Evidence

Reading pass · 2 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2019 EFCAB2 (DRC8) is a calcium-binding protein expressed exclusively in mouse testis and localized specifically to the principal piece of the sperm flagellum. The protein contains two EF-hand motifs (one N-terminal, one C-terminal) and seven α-helices. In vitro assays (Stains-all, ruthenium red staining, and autoradiography) confirmed Ca2+ binding activity of recombinant EFCAB2. Northern blot, western blot, in situ hybridization, immunohistochemistry, 3D structural modeling, in vitro Ca2+-binding assays (Stains-all, ruthenium red, autoradiography) with recombinant protein PloS one Medium 30933994
2018 siRNA-mediated knockdown of Efcab2 in mouse osteoblastic MC3T3-E1 cells reduced osteoblastic cell differentiation (assessed by ALP production and bone mineralization markers), indicating that EFCAB2 enhances osteoblast differentiation. siRNA knockdown in MC3T3-E1 cells, osteoblast differentiation assays (ALP, bone mineralization, marker expression), validated by qPCR Scientific reports Medium 29459627

Source papers

Stage 0 corpus · 11 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2018 Large-Scale Genome-Wide Association Study of East Asians Identifies Loci Associated With Risk for Colorectal Cancer. Gastroenterology 130 30529582
2010 Four patients with speech delay, seizures and variable corpus callosum thickness sharing a 0.440 Mb deletion in region 1q44 containing the HNRPU gene. European journal of medical genetics 72 20382278
2018 Emerging Role of Circular RNAs as Potential Biomarkers for the Diagnosis of Human Diseases. Advances in experimental medicine and biology 64 30259364
2018 High-Throughput Data of Circular RNA Profiles in Human Temporal Cortex Tissue Reveals Novel Insights into Temporal Lobe Epilepsy. Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology 45 29428937
2017 Evaluation of autoantibody signatures in meningioma patients using human proteome arrays. Oncotarget 19 28938569
2018 Understanding the functional role of genistein in the bone differentiation in mouse osteoblastic cell line MC3T3-E1 by RNA-seq analysis. Scientific reports 17 29459627
2012 Identification of gender-specific candidate genes that influence bone microarchitecture in chromosome 1. Calcified tissue international 12 23263656
2019 EFCAB2 is a novel calcium-binding protein in mouse testis and sperm. PloS one 10 30933994
2018 Maternal interchromosomal insertional translocation leading to 1q43-q44 deletion and duplication in two siblings. Molecular cytogenetics 10 29636822
2021 Identification of key carcinogenic genes in Wilms' tumor. Genes & genetic systems 8 34334530
2020 Genetic association of gemcitabine/carboplatin-induced leukopenia and neutropenia in non-small cell lung cancer patients using whole-exome sequencing. Lung cancer (Amsterdam, Netherlands) 8 32683206

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