Mon2 proteins are found from fungi to plants, to human and is a scaffold protein involved in multiple aspects of endo membrane trafficking []. The C-terminal region is essential for Mon2 activity [].
Monensin-resistant homologue 2 (Mon2) is a peripheral membrane protein involved in multiple aspects of endomembrane trafficking [, ]. In Drosophila it has been described to couple endocytosis with actin remodeling []. In budding yeast, Mon2 plays a role in endocytosis and maintenance of vacuolar structure [, ]. Mon2 is distantly related to the guanine nucleotide exchange factors (GEFs) that activate Arf1 on Golgi membranes. However, Mon2 lacks the Sec7 domain that catalyses nucleotide exchange on Arf1 []. In Drosophila it has been described to couple endocytosis with actin remodeling [].
This is theN-terminal domain of Mon2- and BIG1-like proteins, the dimerisation and cyclophilin-binding domain (DCB) [, ]. The N terminus of Mon2 (Ysl2) binds to Arf-Like small GTPase Arl1, and shows homology to brefeldin A-inhibited guanine-exchange factor (BIG) domains []. Mon2 and BIG1-like proteins play an important role in membrane traffic and Golgi homeostasis [, , ]. This domain is sufficient for targeting BIG1 to the Golgi.
This entry represent the HUS regulatory domain found towards the N terminus in guanine nucleotide exchange factors involved Golgi transport, such as budding yeast protein Sec7, protein Mon2 and BIG1-like proteins [, ].Sec7 and its homologues are guanine nucleotide exchange factors (GEFs) involved in the secretory pathway []. The full-length Sec7 functions proximally in the secretory pathway as a protein binding scaffold for the coat protein complexes COPII-COPI []. The COPII-COPI-protein switch is necessary for maturation of the vesicular-tubular cluster, VTC, intermediate compartments for Golgi compartment biogenesis. This N-terminal domain however does not appear to be binding either of the COP or the ARF [].Mon2 is distantly related to the Arf1 guanine nucleotide exchange factors (GEFs), such as Sec7. However, it lacks the Sec7 domain that catalyses nucleotide exchange on Arf1. Instead, Mon2 acts as a scaffold to recruit the Golgi-localised pool of Dop1 [].
This entry represents a HDS (homology downstream of Sec7) domain found towards the C-terminal of guanine nucleotide exchange factors involved Golgi transport, such as budding yeast protein Sec7, protein Mon2 and BIG1-like proteins [, ]. Sec7 is involved in the secretory pathway as a protein binding scaffold for the COPII-COPI protein switch for maturation of the VTC intermediate compartments for Golgi compartment biogenesis []. Sec7 has four conserved HDS1-4 domains which act to integrate the signals from several small GTPases, including Arf1 itself, to switch Sec7 from a strongly autoinhibited to a strongly auto activated form [].
