Smooth muscle contraction is regulated by the cycling of myosin II between on and off states.

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#Id: 7426

#Unit 5. Developmental Biology

During growth, unicellular D. discoideum monitor their cell density relative to that of their bacterial food source by secreting a glycoprotein called prestarvation factor at a constant rate.

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#Id: 7427

#Unit 5. Developmental Biology

When the ratio of PSF relative to that of bacteria exceeds a certain threshold, cells stop proliferating and initiate the expression of genes that are required for their aggregation.

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#Id: 7428

#Unit 5. Developmental Biology

Early on during aggregation, gene expression requires the activity of cAMP-dependent protein kinase.

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#Id: 7429

#Unit 5. Developmental Biology

High PSF to food ratio is upregulate the translation of the PKA catalytic subunit PKA-C.

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#Id: 7430

#Unit 5. Developmental Biology

A second glycoprotein secreted during starvation is CMF (conditioned medium factor)

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#Id: 7431

#Unit 5. Developmental Biology

CMF stimulates gene expression in parallel with PSF, and both signals potentiate cAMP signalling by inducing genes involved in cAMP synthesis and detection