TADA2A

TADA2A Full Name

transcriptional adaptor 2A

TADA2A Introduction

Transcriptional Adaptor 2A (TADA2A), is a protein-coding gene located on human chromosome 17q12‑q21. The gene encodes a 443‑amino acid nuclear protein that functions as a key transcriptional adaptor – a molecular scaffold that connects sequence‑specific transcription factors with the basal transcription machinery and co‑activator complexes. TADA2A is evolutionarily conserved from yeast to humans; its yeast ortholog, Ada2, was originally identified in a genetic screen for mutants that alter transcription of the ADH2 gene. Human TADA2A shares high sequence similarity with its paralog TADA2B (ADA2B), but the two proteins have distinct complex association patterns and non‑overlapping biological functions. TADA2A is essential for normal development and cellular differentiation, and its dysregulation has been linked to several human diseases, including neurodevelopmental disorders and cancer.

Figure 1. Strcuture of TADA2A.

Structural Domains of TADA2A
TADA2A contains two evolutionarily conserved structural modules that mediate its molecular interactions. The first is a SANT (Swi3, Ada2, N‑CoR, and TFIIIB) domain, which is a protein‑protein interaction motif that allows TADA2A to bind other subunits within multi‑protein complexes such as the SAGA and ATAC complexes. The SANT domain in ADA2 proteins is specifically adapted to recognize and stimulate the activity of histone acetyltransferases (HATs) like GCN5/PCAF. The second domain is a ZZ‑type zinc finger, a specialized motif that typically mediates binding to zinc ions and facilitates interactions with chromatin‑associated proteins or DNA. Together, these domains enable TADA2A to act as a central hub that coordinates both histone acetylation and transcription factor recruitment, thereby regulating gene expression at multiple levels.

TADA2A as a Core Component of the SAGA and ATAC Complexes
Unlike its paralog TADA2B, which is exclusively found in the SAGA (Spt‑Ada‑Gcn5‑acetyltransferase) complex, TADA2A is a subunit of two distinct multi‑protein complexes: the SAGA complex and the ATAC (ADA2A‑containing) complex. In the SAGA complex, TADA2A resides within the KAT (lysine acetyltransferase) module together with GCN5 (KAT2A) or PCAF (KAT2B), where it enhances their enzymatic activity and ensures proper substrate recognition. The ATAC complex, which is unique to higher eukaryotes, contains TADA2A, GCN5, and several other subunits (e.g., ATAC2, ATAC3, YEATS2, and ZZZ3) but does not include TADA2B. The ATAC complex is specifically involved in regulating a subset of genes related to cell cycle progression and development. Biochemical studies have shown that TADA2A directly interacts with GCN5, TAF9, and other transcription factors, making it indispensable for the HAT activity of both complexes.

Alternate Names for TADA2A

TADA2A; transcriptional adaptor 2A; ADA2; ADA2A; KL04P; hADA2; TADA2L; transcriptional adapter 2-alpha; ADA2-like protein; transcriptional adaptor 2 alpha;