Functions as a component of the DNA-binding general transcription factor complex TFIID, the RNA polymerase II associated general transcription factor complex TFIIF, and the chromatin-remodeling complex SWI/SNF (PubMed:10788514, PubMed:12138208, PubMed:12516863, PubMed:9618449). Binding of TFIID to a promoter (with or without TATA element) is the initial step in preinitiation complex (PIC) formation (PubMed:10788514, PubMed:12138208, PubMed:12516863, PubMed:9618449). TFIID plays a key role in the regulation of gene expression by RNA polymerase II through different activities such as transcription activator interaction, core promoter recognition and selectivity, TFIIA and TFIIB interaction, chromatin modification (histone acetylation by TAF1), facilitation of DNA opening and initiation of transcription (PubMed:10788514, PubMed:12138208, PubMed:12516863, PubMed:9618449). TFIIF is essential for the initiation of transcription by RNA polymerase II (PubMed:10788514, PubMed:12138208, PubMed:12516863, PubMed:9618449). TFIIF functions include the recruitment of RNA polymerase II to the promoter bound DNA-TBP-TFIIB complex, decreasing the affinity of RNA polymerase II for non-specific DNA, allowing for the subsequent recruitment of TFIIE and TFIIH, and facilitating RNA polymerase II elongation (PubMed:10788514, PubMed:12138208, PubMed:12516863, PubMed:9618449, PubMed:30385749). TAF14 acts as a chromatin reader that specifically recognizes and binds histones that are acylated (PubMed:26341557, PubMed:27089029). Recognizes and binds histone H3 acetylated or crotonylated at 'Lys-9' (H3K9ac and H3K9cr, respectively), with some preference for crotonylated lysine (PubMed:26341557, PubMed:27089029, PubMed:30385749). Component of the SWI/SNF complex, an ATP-dependent chromatin-remodeling complex, is required for the positive and negative regulation of gene expression of a large number of genes (PubMed:12672490). It changes chromatin structure by altering DNA-histone contacts within a nucleosome, leading eventually to a change in nucleosome position, thus facilitating or repressing binding of gene-specific transcription factors (PubMed:12672490). Component of the histone acetyltransferase NuA3 complex, that acetylates Lys-14 of histone H3. Recruitment of NuA3 to nucleosomes requires methylated histone H3 (PubMed:17157260). In conjunction with the FACT complex, NuA3 may be involved in transcriptional regulation (PubMed:17157260). Does not bind DNA (PubMed:30385749).