GJA5

GJA5 (Gap Junction Alpha-5 Protein), also known as Connexin 40 (Cx40), is a protein that in humans is encoded by the GJA5 gene. This protein is a member of the connexin family, which plays a critical role in the formation of gap junctions. Gap junctions are specialized intercellular connections that facilitate direct cell-to-cell communication. This communication is essential for various physiological processes, including the regulation of cardiac function, vascular tone, and developmental processes.

Function

GJA5 is predominantly expressed in endothelial cells and cardiac myocytes, where it forms gap junction channels that allow the passage of ions and small molecules between adjacent cells. This intercellular communication is crucial for the synchronized contraction of the heart and for maintaining vascular homeostasis. In the heart, Cx40 pairs with other connexins, such as Connexin 43 (Cx43) and Connexin 37 (Cx37), to form heteromeric channels with distinct properties, which are essential for the propagation of electrical impulses across the atria and the conduction system.

Genetic and Clinical Significance

Mutations in the GJA5 gene have been associated with various cardiovascular disorders, including atrial fibrillation, congenital heart disease, and hypertension. These conditions often result from impaired gap junction communication, leading to disrupted cardiac conduction and altered vascular function. Additionally, the expression levels of Cx40 have been found to be altered in several pathological conditions, suggesting its potential role in disease progression and as a target for therapeutic intervention.

Regulation

The expression and function of Cx40 are regulated by various factors, including transcription factors, hormones, and mechanical stress. This regulation ensures the proper formation and function of gap junctions in response to physiological and pathological stimuli. For example, shear stress has been shown to upregulate Cx40 expression in endothelial cells, highlighting the importance of mechanical forces in vascular gap junction communication.

Research and Therapeutic Potential

Research on GJA5 and its encoded protein, Cx40, continues to uncover its roles in health and disease. Understanding the molecular mechanisms underlying Cx40 function and regulation provides insights into the pathogenesis of cardiovascular diseases and identifies potential therapeutic targets. For instance, modulating Cx40 expression or function has been proposed as a strategy to restore normal cardiac conduction in arrhythmias or to improve vascular function in hypertension.

See Also

• Connexin
• Gap junction
• Cardiac conduction system
• Atrial fibrillation
• Congenital heart disease

References

Cardiovascular disease A-Z

Most common cardiac diseases

• Cardiac arrhythmia‎
• Cardiogenetic disorders‎
• Cardiomegaly‎
• Cardiomyopathy‎
• Cardiopulmonary resuscitation‎
• Chronic rheumatic heart diseases‎
• Congenital heart defects‎
• Heart neoplasia‎
• Ischemic heart diseases‎
• Pericardial disorders
• Syndromes affecting the heart‎
• Valvular heart disease‎

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

A

• Accelerated idioventricular rhythm
• Acute decompensated heart failure
• Arteriosclerotic heart disease
• Athletic heart syndrome
• Atrial flutter
• Atrioventricular fistula
• Cardiovascular disease in Australia
• Autoimmune heart disease

B

• Brown atrophy of the heart

C

• Ebb Cade
• Cardiac allograft vasculopathy
• Cardiac amyloidosis
• Cardiac asthma
• Cardiac tamponade
• Cardiogenic shock
• Cardiogeriatrics
• Cardiorenal syndrome
• Cardiotoxicity
• Carditis
• Coronary artery aneurysm
• Coronary artery anomaly
• Coronary artery disease
• Spontaneous coronary artery dissection
• Coronary artery ectasia
• Coronary occlusion
• Coronary steal
• Coronary thrombosis
• Coronary vasospasm
• Cœur en sabot
• Coxsackievirus-induced cardiomyopathy

D

• Duke Treadmill Score
• Duroziez's disease

E

• Eisenmenger's syndrome
• Embryocardia
• Endocardial fibroelastosis
• Eosinophilic myocarditis

H

• Heart attack
• Heart failure
• Heart failure with preserved ejection fraction
• Heart to Heart (1949 film)
• High-output heart failure
• Hyperdynamic precordium

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

I

• Idiopathic giant-cell myocarditis
• Interventricular dyssynchrony
• Intraventricular dyssynchrony
• Isolated atrial amyloidosis

K

• Keshan disease

L

• Loeffler endocarditis

M

• Mydicar
• Myocardial bridge
• Myocardial disarray
• Myocardial rupture
• Myocardial scarring
• Myocardial stunning
• Myocarditis

N

• Nonbacterial thrombotic endocarditis

O

• OLR1
• Ostial disease

P

• Papillary fibroelastoma
• Pathophysiology of heart failure
• Postpericardiotomy syndrome
• Pulmonary vein stenosis

R

• Right axis deviation
• Roemheld syndrome

S

• Saturated fat and cardiovascular disease
• SCAR-Fc
• Shone's syndrome
• Strain pattern
• Subacute bacterial endocarditis
• Sudden cardiac death of athletes

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

T

• Traumatic cardiac arrest

V

• Ventricular aneurysm
• Vibroacoustic disease
• Viral cardiomyopathy

W

• Waon therapy