Question

You may choose more than one answer. Which of the following phosphatases activate their substrates by phosphate group removal?

PPPs (phosphoprotein phosphatases)

PHLPP (PH domain and leucine rich repeat protein phosphatases) isofroms

Protein kinase C

CD45 antigen (protein phosphatase, receptor type C)

Answer 1

PPPs (phosphoprotein phosphatases), PHLPP (PH domain and leucine rich repeat protein phosphatases) isofroms, CD45 antigen (protein phosphatase, receptor type C) dephosphorylates their substrate i.e. removal of phosphate group from them but Protein kinase C phosphorylates its substrate.

At high concentration of glucose in the blood, Phosphoprotein phosphatase gets activated by insulin harmone. The enzyme then dephosphorylate other enzymes like phosphorylase kinase, glycogen phosphorylase, and glycogen synthase to maintain the level of glucose.

PH domain and leucine rich repeat protein phosphatases) isofroms are a type of protein phosphatase which are involved in regulation of Akt and Protein Kinase C (PKC) signaling. It mediates dephosphorylation at the C-terminal domain, hydrophobic motif of members of the AGC Ser/Thr protein kinase family. Dephosphprylation of ser in Akt signalling induces apoptosis signalling and suppress tumor growth.

CD45 antigen (protein phosphatase, receptor type C), is a tyrosine-protein phosphatase required for T-cell activation through the antigen receptor. It acts as a positive regulator of T-cell coactivation upon binding to DPP4. This PTPase domain has enzymatic activity, whereas the second one affects the substrate specificity of the first one. Upon T-cell activation, SKAP1 and FYN gets dephosphorylates. It also dephosphorylates LYN, and thereby modulating its activity.