CTNNA1
Description
The CTNNA1 (catenin alpha 1) is a protein-coding gene located on chromosome 5.
αE-catenin, also known as Catenin alpha-1 is a protein that in humans is encoded by the CTNNA1 gene. αE-catenin is highly expressed in cardiac muscle and localizes to adherens junctions at intercalated disc structures where it functions to mediate the anchorage of actin filaments to the sarcolemma. αE-catenin also plays a role in tumor metastasis and skin cell function.
== Structure == Human αE-catenin protein is 100.0 kDa and 906 amino acids. Catenins (α,β,and γ (also known as plakoglobin)) were originally identified in complex with E-cadherin, an epithelial cell adhesion protein. αE-catenin is highly expressed in cardiac muscle and is homologous to the protein vinculin; however, aside from vinculin, αE-catenin has no homology to established actin-binding proteins. The N-terminus of αE-catenin binds β-catenin or γ-catenin/plakoglobin, and the C-terminus binds actin directly or indirectly via vinculin or α-actinin.
== Function == Though αE-catenin exhibits substantial expression in cardiac muscle, αE-catenin is most well known for role in metastasizing tumor cells. αE-catenin also plays a role in epithelial tissue, both at adherens junctions and in signaling pathways. In cardiomyocytes, αE-catenin is present in cell to cell regions known as adherens junctions which lie within intercalated discs; these junctions anchor the actin cytoskeleton to the sarcolemma and provide strong cell adhesion.
CTNNA1, also known as alpha-E-catenin, plays a critical role in cell adhesion by associating with the cytoplasmic domain of various cadherins. This association forms a complex that connects to the actin filament network, which is essential for cadherin-mediated cell adhesion. CTNNA1 can bind to both E-cadherin and N-cadherin. While initially believed to be a stable component of E-cadherin/catenin adhesion complexes and directly linking cadherins to the actin cytoskeleton at adherens junctions, further research suggests a more dynamic interaction. CTNNA1 has been shown not to bind directly to F-actin when assembled in the complex, indicating a different mechanism for connecting actin to adherens junction components. The homodimeric form of CTNNA1 might regulate actin filament assembly and inhibit actin branching by competing with the Arp2/3 complex for binding to actin filaments. CTNNA1 is also involved in regulating the nuclear accumulation of WWTR1/TAZ, YAP1, and TGFβ1-dependent SMAD2 and SMAD3, suggesting a role in signaling pathways. Additionally, CTNNA1 may play a crucial role in cell differentiation.
CTNNA1 is also known as CAP102, MDBS2, MDPT2.
