Chromatin reader component of some histone acetyltransferase (HAT) SAGA-type complexes like the TFTC-HAT, ATAC or STAGA complexes (PubMed:19103755, PubMed:20850016, PubMed:26421618, PubMed:21685874, PubMed:26578293). SGF29 specifically recognizes and binds methylated 'Lys-4' of histone H3 (H3K4me), with a preference for trimethylated form (H3K4me3) (PubMed:20850016, PubMed:26421618, PubMed:21685874, PubMed:26578293). In the SAGA-type complexes, SGF29 is required to recruit complexes to H3K4me (PubMed:20850016). Involved in the response to endoplasmic reticulum (ER) stress by recruiting the SAGA complex to H3K4me, thereby promoting histone H3 acetylation and cell survival (PubMed:23894581). Interacts with dimethylated and trimethylated 'Lys-4' of histone H3 (H3K4me2 and H3K4me3), with a preference for the trimethylated form (H3K4me3) (PubMed:21685874, PubMed:26578293). Component of some SAGA-type complexes (PubMed:20850016). Component of the ADA2A-containing complex (ATAC), composed of KAT14, KAT2A, TADA2L, TADA3L, ZZ3, MBIP, WDR5, YEATS2, CCDC101 and DR1 (PubMed:19103755). Interacts with TADA3L, GCN5L2, SUPT3H and MYC (By similarity). The SGF29 C-terminal (also named tudor-like) domain mediates binding to methylated 'Lys-4' of histone H3 (H3K4me), with a preference for trimethylated form (H3K4me3). Belongs to the SGF29 family.