Protein Posttranslational Modifications: Roles in Aging and Age-Related Disease

Figure 5

Possible strategies for spatial and temporal regulation of polar localization. (a) Asymmetric polar patterns can be naturally produced by a cell division event. Left: bipolar to old-pole localization; right: propagation of an old pole accumulation. Misfolded proteins produced in the progeny accumulate onto the existing polar aggregate. Eventually, de novo polar accretions can appear in progeny that did not acquire a polar focus (top cell), for example, after new protein synthesis. (b) The ability of some proteins to self-assemble and thereby to localize at the poles could be influenced by modifications such as phosphorylation upon a specific signal. The question mark indicates a hypothetical step. (c) The concentration of a self-assembling protein or oligomer and, thereby, its propensity to multimerize can be modified locally through protein-protein interaction with a partner whose subcellular distribution is asymmetric. In step 1, the protein (blue) has an asymmetric distribution inherent to a cell cycle event. The concentration of the diffusing protein oligomer (red) increases locally owing to interaction with the asymmetric protein. In step 2, the self-assembly of a protein or oligomer leads to the formation of a large structure at the pole. This provides spatial and temporal regulation to a multimerization-dependent polar localization. Reproduced with permission from Laloux and Jacobs-Wagner [169].

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