RCC1like

RCC1-like refers to a family of proteins characterized by RCC1-like repeats (RLDs), named after the regulator of chromosome condensation 1 (RCC1). The RCC1-like domain is a conserved motif that mediates protein-protein interactions and can function in guanine nucleotide exchange factor activity toward Ran GTPase in many contexts.

The defining feature is RCC1-like domain(s) typically at the C-terminus, often forming a beta-propeller structure; N-terminal regions are variable and may carry targeting signals, low-complexity regions, or additional domains; this modularity underlies diverse subcellular localizations and interactions.

Function: In canonical RCC1, the RCC1-like domain acts as a guanine nucleotide exchange factor for Ran, establishing the RanGTP gradient that drives nuclear transport and spindle assembly during mitosis; RCC1-like proteins may retain GEF activity or use the domain as a scaffolding module to regulate Ran-dependent processes; some family members participate in chromatin organization or cell cycle control.

Localization and regulation: RCC1 and relatives can localize to the nucleus, kinetochores, centrosomes, mitochondria, or cytoplasm, depending on signals and isoforms; their activity is regulated by phosphorylation, localization cues, and interaction with other Ran pathway components; changes in expression or function can affect nucleocytoplasmic transport and mitotic progression.

Evolution and significance: The RCC1-like domain is conserved across eukaryotes, with lineage-specific expansions; studying RCC1-like proteins informs understanding of Ran signaling, nuclear transport, and cell division; dysregulation has been linked to disease in some contexts.