Mob1

Mob1 is a conserved family of proteins named after their yeast counterpart Mob1p. In Saccharomyces cerevisiae, Mob1p functions as a regulatory subunit of the protein kinases Dbf2p and Dbf20p, forming the MEN/Mak pathway that promotes mitotic exit and cytokinesis. Homologs are found across fungi, animals, and plants.

In multicellular organisms, MOB1 proteins act as adaptor or activating subunits for a subset of kinases in the NDR/LATS family, including LATS1/2 and NDR1/2 in mammals and Mats in Drosophila. By binding these kinases, MOB1 promotes their phosphorylation and activity, enabling proper control of cell proliferation, apoptosis, and tissue growth via the Hippo signaling pathway.

Structure and localization: MOB1 proteins contain a conserved MOB domain and typically function as cytoplasmic adaptors; interaction with kinases can influence subcellular localization and activity. The human proteins MOB1A and MOB1B are encoded by MOB1A and MOB1B genes, respectively.

Biological roles: in yeast, MOB1 is essential for exit from mitosis; in metazoans, MOB1 participates in growth control and organ size regulation; in the Hippo pathway, MOB1 modulates YAP/TAZ activity, thereby affecting gene expression programs linked to proliferation and differentiation.

Clinical relevance: dysregulation of MOB1 or its kinase partners has been associated with cancer and developmental defects in model organisms; MOB1 remains a focus of research as a potential component of anti-cancer strategies targeting the Hippo pathway.