In the absence of Frizzled activation, β-catenin is modified and:

In the absence of Frizzled activation, β-catenin is marked for degradation as part of the Wnt signaling pathway. When Frizzled receptors are not activated, there is no stabilization of β-catenin, which leads to its phosphorylation by a protein complex that includes axin and glycogen synthase kinase 3 (GSK3). Phosphorylation signals β-catenin for recognition by the proteasome, where it is tagged and subsequently degraded into smaller peptides.

This process is crucial because it prevents β-catenin from accumulating in the cytoplasm and translocating to the nucleus, where it would otherwise promote the expression of target genes involved in cell proliferation and differentiation. Thus, in the absence of signaling from Frizzled, the continuous degradation of β-catenin helps maintain normal cellular functions and prevents abnormal growth or signaling.

The other options do not accurately reflect what happens to β-catenin in the absence of Frizzled activation. β-catenin does not get translocated to the Golgi for secretion, nor is it engulfed by lysosomes for degradation. Additionally, it is not stored in vesicles; rather, it is actively targeted for destruction when Frizzled is not signaling. This