Barrier-to-autointegration factor (breakpoint cluster region protein 1, BANF1, BAF, BCRG1)

Function: - roles in nuclear assembly, chromatin organization, gene expression & gonad development - may compress chromatin structure & be involved in membrane recruitment & chromatin decondensation during nuclear assembly - contains 2 nonspecific dsDNA-binding sites which may promote DNA cross-bridging. - homodimer, heterodimerizes with BAFL - binds non nonspecifically to double-stranded DNA, & is found as a hexamer or dodecamer upon DNA binding - binds to LEM domain-containing nuclear proteins including LEMD3/MAN1, TMPO/LAP2 & EMD (emerin) - interacts with CRX & LMNA (lamin-A) - binds linker histone H1.1 & core histones H3 with in vitro affinities of 500-900 & 100-200 nM. - partially phosphorylated on serine - Ser-4 phosphorylation may block BAF ability to promote EMD binding to lamins in vitro. - non phosphorylated BAF seems to enhances binding between EMD & LMNA Structure: - belongs to the BAF family - has a helix-hairpin-helix (HhH) structural motif conserved among proteins that bind nonspecifically to DNA - LEM domain proteins bind centrally on the BAF dimer, DNA binds to the left & right sides Compartment: - nucleus, cytoplasm - significantly enriched at the nuclear inner membrane, diffusely throughout nucleus during interphase & concentrated at the chromosomes during M-phase Expression: - widely expressed - expressed in colon, brain, heart, kidney, liver, lung, ovary, pancreas, placenta, prostate, skeletal muscle, small intestine, spleen, testis - not detected in thymus & peripheral blood leukocytes Pathology: - exploited by retroviruses for inhibiting self-destructing autointegration of retroviral DNA, thereby promoting integration of viral DNA into the host chromosome - interacts with HIV-1 pre-integration complex in cytoplasm by binding to viral matrix protein & GAG polyprotei - may be included in HIV-1 virions via its interaction with viral GAG polyprotein

General

DNA-binding protein phosphoprotein

Properties

SIZE: MW = 10 kD entity length = 89 aa COMPARTMENT: cytoplasm cell nucleus MOTIF: Ser phosphorylation site {S4}

Database Correlations

UniProt O75531 Pfam PF02961

References

UniProt :accession O75531