Details

Autor(en) / Beteiligte

• Bagde, Saket R.
• Fromme, J. Christopher

Titel

The TRAPP complexes: discriminating GTPases in context

Ist Teil von

• FEBS letters, 2023-03, Vol.597 (6), p.721-733

Ort / Verlag

England

Erscheinungsjahr

2023

Quelle

Wiley-Blackwell Journals

Beschreibungen/Notizen

• Correct localization of Rab GTPases in cells is critical for proper function in membrane trafficking. Guanine‐nucleotide exchange factors (GEFs) act as the primary determinants of Rab localization by activating and stabilizing their Rab substrates on specific organelle and vesicle membranes. The TRAPP complexes TRAPPII and TRAPPIII are two related GEFs that use the same catalytic site to activate distinct Rabs, Rab11 and Rab1, respectively. The Rab C‐terminal hypervariable domain (HVD) is an important specificity determinant for the budding yeast TRAPP complexes, with the length of the HVD playing a critical role in counter‐selection. Several recent studies have used cryo‐EM to illuminate how the yeast and metazoan TRAPP complexes identify and activate their substrates. This review summarizes recently characterized Rab substrate selection mechanisms and highlights how the membrane surface provides critical context for the GEF‐GTPase interactions. The TRAPP complexes are guanine‐nucleotide exchange factors that activate the Rab1 and Rab11 GTPases. Recent studies have structurally and biochemically characterized how the distinct but related TRAPPII and TRAPPIII complexes identify their specific Rab substrates. In this review, we highlight how the lipid membrane surface provides important context enabling the complexes to discriminate between Rab1 and Rab11.