Inherited mutations in the BRCA1 gene predispose to a higher risk of 
breast/ovarian cancer. The BRCA1 tumor suppressor is a 1863 amino acid protein 
with multiple protein interaction domains that facilitate its roles in 
regulating DNA repair and maintenance, cell cycle progression, transcription, 
and cell survival/apoptosis. BRCA1 was first identified as a nuclear 
phosphoprotein, but has since been shown to contain different transport 
sequences including nuclear export and nuclear localization signals that enable 
it to shuttle between specific sites within the nucleus and cytoplasm, including 
DNA repair foci, centrosomes, and mitochondria. BRCA1 nuclear transport and 
ubiquitin E3 ligase enzymatic activity are tightly regulated by the BRCA1 
dimeric binding partner BARD1 and further modulated by cancer mutations and 
diverse signaling pathways. This paper will focus on the transport, dynamics, 
and multiple intracellular destinations of BRCA1 with emphasis on how regulation 
of these events has impact on, and determines, a broad range of important 
cellular functions.