GJA8 Membrane Protein Introduction

Introduction of GJA8

Gap junction alpha-8 protein (GJA8), known as connexin 50 (Cx50), is a protein which in humans is encoded by the GJA8 gene. Cx50 is a connexin isoform of 50 kDa. The GJA8 gene locates on human chromosome 1. GJA8 is associated with maintaining lens opacity and proper lens development. Impaired GJA8 could lead to small eye problems, small mirror size and cataracts.

Basic Information of GJA8
Protein Name	Gap junction alpha-8 protein
Gene Name	GJA8
Aliases	Connexin-50
Organism	Homo sapiens (Human)
UniProt ID	P48165
Transmembrane Times	4
Length (aa)	433
Sequence	MGDWSFLGNILEEVNEHSTVIGRVWLTVLFIFRILILGTAAEFVWGDEQSDFVCNTQQPGCENVCYDEAFPISHIRLWVLQIIFVSTPSLMYVGHAVHYVRMEEKRKSREAEELGQQAGTNGGPDQGSVKKSSGSKGTKKFRLEGTLLRTYICHIIFKTLFEVGFIVGHYFLYGFRILPLYRCSRWPCPNVVDCFVSRPTEKTIFILFMLSVASVSLFLNVMELGHLGLKGIRSALKRPVEQPLGEIPEKSLHSIAVSSIQKAKGYQLLEEEKIVSHYFPLTEVGMVETSPLPAKPFNQFEEKISTGPLGDLSRGYQETLPSYAQVGAQEVEGEGPPAEEGAEPEVGEKKEEAERLTTEEQEKVAVPEGEKVETPGVDKEGEKEEPQSEKVSKQGLPAEKTPSLCPELTTDDARPLSRLSKASSRARSDDLTV

Function of GJA8 Membrane Protein

GJA8 has been shown to form functional hemichannels and promote lens fiber differentiation in vitro, independent of its channel forming ability. Gap-junction channels allow direct exchange of ions and small signal/metabolism molecules between adjacent cells and play a key role in many physiological processes. GJA8 is found in the cytoplasm and nucleus of glial cells, astrocytes, and oligodendrocyte-derived cells. Similar expression patterns were also found in the primary culture of mature astrocytes. Furthermore, when epSPC and activated epSPCi were used to differentiate into mature oligodendrocytes, the opposite expression profile of nuclear GJA8 was observed, suggesting that this ion channel has a different role in the spinal cord during intercellular communication. GJA8 was detected in vivo by immunohistochemistry, showing a defined position in the gray matter of non-lesional tissues.

Fig.1 The membrane topology of Gap junction alpha-8 protein. (Beyer, 2013)

Application of GJA8 Membrane Protein in Literature

Šeda O., et al. Heterozygous Connexin 50 Mutation Affects Metabolic Syndrome Attributes in Spontaneously Hypertensive Rat. Lipids in Health and Disease. 2016, (15): 199. PubMed ID: 27871290

The results demonstrate that the mutation of GJA8 in heterozygous state affects significantly the lipid profile and the oxidative stress parameters in the spontaneously hypertensive rat strain.
Wang E., et al. Connexin 50 Regulates Surface Ball-and-Socket Structures and Fiber Cell Organization. Investigative Ophthalmology & Visual Science. 2016, (57.7):3039-3046. PubMed ID: 27281269

This article reveals that loss of Cx50-mediated coupling, BS disruption, and altered F-actin in GJA8 KO fibers contribute to the small lens and mild cataract phenotypes.
Tong X., et al. Charge at the 46th residue of connexin 50 is crucial for the gap-junctional unitary conductance and transjunctional voltage-dependent gating. The Journal of Physiology. 2014, 592(23):5187-5202. PubMed ID: 25260631

These data indicate that the pore surface charges at the TM1/E1 border domain of GJA8 channel are crucial for the γ_j and V_j gating properties.
Rodriguez-Jimenez F.J., et al. Connexin 50 Expression in Ependymal Stem Progenitor Cells after Spinal Cord Injury Activation. International Journal of Molecular Sciences. 2015, 16 (11): 26608–26618. PubMed ID: 26561800

The results suggest a minor or detrimental contribution of GJA8 in spinal cord injury regeneration.
Min H-Y., et al. Targeted Genes Sequencing Identified a Novel 15 bp Deletion on GJA8 in a Chinese Family with Autosomal Dominant Congenital Cataracts. Chinese Medical Journal. 2016,129(7):860-867. PubMed ID: 26996484

MD simulation revealed that the introduction of the deletion destabilized the GJA8 gap junction channel, indicating the deletion as a dominant-negative mutation.

GJA8 Preparation Options

To obtain the soluble and functional target protein, the versatile Magic™ membrane protein production platform in Creative Biolabs enables many flexible options, from which you can always find a better match for your particular project. Aided by our versatile Magic™ anti-membrane protein antibody discovery platform, we also provide customized anti-GJA8 antibody development services.

Creative Biolabs' skillful scientists are glad to leverage our expertise and advanced technologies to help you with the member protein research. If you are interested, please feel free to contact us for more details.

Reference

Beyer Eric C. (2013). Connexin Mutants and Cataracts. Frontiers in Pharmacology.4,43.

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