Fig. 9

Proposed model illustrating the regulation of lipogenesis in cattle by Vitamin A through FABP4. Within physiological systems, vitamin A is enzymatically oxidized by alcohol dehydrogenase and aldehyde dehydrogenase to generate RA. RA binds to RAR and RXR, forming heterodimers that transcriptionally regulate ZFP423, a master adipogenic determinant. ZFP423 directly governs EBF2 expression, which in turn activates FABP4 via behenic acid-mediated signaling cascades. FABP4 upregulates lipid metabolism and lipogenesis markers, thereby driving IMAs differentiation. Concurrently, RA accelerates G1/S phase progression in IMAs by elevating CDK2 and PCNA expression, enhancing mitotic activity. These dual regulatory axes-differentiation via FABP4 and proliferation via CDK2/PCNA—collectively establish RA as a critical modulator of bovine IMF deposition. Solid lines represent established mechanisms, while dotted lines indicate potential or unknown interactions