# TBC1D30

## Overview
TBC1D30, or TBC1 domain family member 30, is a gene that encodes the protein TBC1 domain family member 30, which is a member of the TBC (Tre-2/Bub2/Cdc16) domain family. This protein functions primarily as a GTPase-activating protein (GAP) for Rab8, a key regulator in the formation and function of primary cilia, essential cellular structures that serve as signaling hubs. The protein's activity is crucial in various cellular processes including cell signaling pathways, intracellular trafficking, and the regulation of cellular architecture. TBC1D30's role in these processes makes it significant in understanding cellular function and development, as well as in the study of diseases where these pathways are disrupted. The protein's interaction with other molecular components within the cell highlights its importance in the delicate balance of cellular signaling required for proper cellular function and development.

## Structure
TBC1D30, or TBC1 domain family member 30, encodes a protein that is part of the TBC (Tre-2/Bub2/Cdc16) domain family, which is integral in regulating cell signaling pathways influencing cell growth and development. The protein encoded by TBC1D30 can be structurally analyzed at multiple levels: primary, secondary, tertiary, and quaternary.

The primary structure of TBC1D30 consists of a linear sequence of amino acids, which includes the characteristic TBC domain responsible for its function in GTPase activation. This activation is crucial for various cellular processes. The secondary structure features common motifs such as alpha helices and beta sheets, which are typical in many proteins and are important for the protein's stability and function.

At the tertiary level, TBC1D30 folds into a unique three-dimensional structure that is necessary for its biological activity. This structure allows for the interaction with other molecules and proteins within the cell, facilitating its role in signaling pathways.

The quaternary structure of TBC1D30 involves its interaction and possibly forming complexes with other proteins, which could influence its function and localization within the cell. Additionally, TBC1D30 may undergo post-translational modifications such as phosphorylation, which can further regulate its activity and stability. Various splice variant isoforms of TBC1D30 also exist, potentially altering its functional and interaction dynamics within the cell.

## Function
TBC1D30, a member of the Tre2-Bub2-Cdc16 (TBC) protein family, functions as a GTPase-activating protein (GAP) specifically for the Rab8 GTPase. This protein plays a significant role in the regulation of cellular architecture and signaling pathways, particularly through its involvement in the formation and function of primary cilia, which are crucial signaling hubs on the cell surface (Barr2014Rab). Primary cilia are essential for various signaling pathways that govern cellular and tissue architecture, especially during development and in disease states where these pathways might be disrupted.

The activity of TBC1D30 in modulating Rab8 activity is critical in ciliogenesis. By acting as a GAP for Rab8, TBC1D30 can suppress the formation of primary cilia by interfering with Rab8a activity, thus indirectly influencing the ciliogenesis process (Čajánek2014Cep164). This suppression highlights the protein's role in the delicate balance of cellular signaling required for proper cellular function and development.

Overall, TBC1D30 is integral to the regulation of intracellular trafficking and signaling, impacting crucial cellular processes and potentially influencing disease pathology when dysregulated.

## Interactions
TBC1D30, a GTPase activating protein (GAP) for Rab8, plays a significant role in the regulation of cellular processes through its interactions with other proteins. It is specifically enriched at primary cilia, suggesting interactions with components of the ciliary structure or signaling pathways associated with cilia (Barr2014Rab). The protein's GAP activity facilitates the conversion of Rab8 from its active GTP-bound form to an inactive GDP-bound form, which is crucial for the proper functioning and regulation of Rab8-dependent pathways, including those involved in cell shape changes, migration, and ciliogenesis (Peränen2011Rab8).

Furthermore, TBC1D30's overexpression has been shown to suppress primary cilium (PC) formation by interfering with Rab8a activity. This interaction does not affect the recruitment of IFT81 or the removal of CP110 from centrioles, indicating that while TBC1D30 modulates Rab8a activity, it does not directly influence these specific events in ciliogenesis (Čajánek2014Cep164). These interactions underline the critical role of TBC1D30 in cellular trafficking and signaling pathways, particularly in the context of primary cilia and Rab8 regulation.


## References


[1. (Peränen2011Rab8) Johan Peränen. Rab8 gtpase as a regulator of cell shape. Cytoskeleton, 68(10):527–539, September 2011. URL: http://dx.doi.org/10.1002/cm.20529, doi:10.1002/cm.20529. (117 citations) 10.1002/cm.20529](https://doi.org/10.1002/cm.20529)

[2. (Barr2014Rab) Francis A. Barr. Rab GEFs and GAPs: The Enigma Variations, pages 81–106. Springer International Publishing, 2014. URL: http://dx.doi.org/10.1007/978-3-319-07761-1_5, doi:10.1007/978-3-319-07761-1_5. (1 citations) 10.1007/978-3-319-07761-1_5](https://doi.org/10.1007/978-3-319-07761-1_5)

[3. (Čajánek2014Cep164) Lukáš Čajánek and Erich A. Nigg. Cep164 triggers ciliogenesis by recruiting tau tubulin kinase 2 to the mother centriole. Proceedings of the National Academy of Sciences, June 2014. URL: http://dx.doi.org/10.1073/pnas.1401777111, doi:10.1073/pnas.1401777111. (189 citations) 10.1073/pnas.1401777111](https://doi.org/10.1073/pnas.1401777111)