SAM complex

Definition

Target type: cellularcomponent

A large complex of the mitochondrial outer membrane that mediates sorting of some imported proteins to the outer membrane and their assembly in the membrane; functions after import of incoming proteins by the mitochondrial outer membrane translocase complex. [PMID:12891361]

The SAM complex, or S-adenosylmethionine complex, is a multiprotein complex involved in various cellular processes, primarily in the translation and modification of RNA molecules. Its cellular component is the **nucleus**, specifically **nucleoli**, where it plays a crucial role in ribosomal biogenesis.

The SAM complex is a **large and dynamic structure** composed of several subunits, including:

* **Fibrillarin (FBL):** This protein has methyltransferase activity and is essential for methylation of rRNA during ribosome assembly.
* **Nop56/58 (NOP56/58):** These proteins are involved in RNA processing and ribosome assembly.
* **Gar1:** This protein is a GTPase that regulates the assembly and function of the SAM complex.
* **Other associated proteins:** These proteins include nucleolin, snRNA, and various small nucleolar ribonucleoproteins (snoRNPs), each contributing to the complex's diverse functionalities.

**The SAM complex's localization within the nucleoli is tightly regulated.** Its assembly and disassembly are essential for the dynamic nature of ribosome biogenesis. The complex interacts with pre-ribosomal RNA (pre-rRNA) molecules, facilitating their processing and modification.

**In summary, the SAM complex's cellular component is the nucleus, specifically the nucleoli, where it orchestrates key steps in ribosome biogenesis by modifying and processing pre-rRNA molecules.**'
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Proteins (1)

Compounds (1)