This entry represents a group of C2H2-type Zinc finger proteins, including a transcription factor yin and yang 1 (YY1). YY1 has been shown to regulate cell proliferation and differentiation, and its deficiency in mice results in peri-implantation lethality during embryonic development. It has also been linked to cancers [].Proteins in this entry also include YY2. It may antagonize YY1 and function in development and differentiation [].
YY1-associated protein 1 enhances transcription activation by the multifunctional zinc finger transcription factor YY1 []. It is also known as HCCA2 (hepatocellular carcinoma-associated gene 2). It is an oncogenic driver in hepatocellular carcinoma []and may play a role in cell cycle regulation []. It is component of the INO80 chromatin remodeling complex which is responsible for transcriptional regulation, DNA repair, and replication [].
Phosphotyrosyl phosphatase activator (PTPA, also known as protein phosphatase 2A activator) proteins stimulate the phosphotyrosyl phosphatase (PTPase) activity of the dimeric form of protein phosphatase 2A (PP2A). PTPase activity in PP2A (in vitro) is relatively low when compared to the better recognised phosphoserine/ threonine protein phosphorylase activity. It also reactivates the serine/threonine phosphatase activity of an inactive form of PP2A. The specific biological role of PTPA is unknown. PTPA has been suggested to play a role in the insertion of metals to the PP2A catalytic subunit (PP2Ac) active site, to act as a chaperone, and more recently, to have peptidyl prolyl cis/trans isomerase activity that specifically targets human PP2Ac [, , , , , ]. Together, PTPA and PP2A constitute an ATPase and it has been suggested that PTPA alters the relative specificity of PP2A from phosphoserine/phosphothreonine substrates to phosphotyrosine substrates in an ATP-hydrolysis-dependent manner. Basal expression of PTPA depends on the activity of a ubiquitous transcription factor, Yin Yang 1 (YY1). The tumour suppressor protein p53 can inhibit PTPA expression through an unknown mechanism that negatively controls YY1 [].
Phosphotyrosyl phosphatase activator (PTPA, also known as protein phosphatase 2A activator) proteins stimulate the phosphotyrosyl phosphatase (PTPase) activity of the dimeric form of protein phosphatase 2A (PP2A). PTPase activity in PP2A (in vitro) is relatively low when compared to the better recognised phosphoserine/ threonine protein phosphorylase activity. It also reactivates the serine/threonine phosphatase activity of an inactive form of PP2A. The specific biological role of PTPA is unknown. PTPA has been suggested to play a role in the insertion of metals to the PP2A catalytic subunit (PP2Ac) active site, to act as a chaperone, and more recently, to have peptidyl prolyl cis/trans isomerase activity that specifically targets human PP2Ac [, , , , , ]. Together, PTPA and PP2A constitute an ATPase and it has been suggested that PTPA alters the relative specificity of PP2A from phosphoserine/phosphothreonine substrates to phosphotyrosine substrates in an ATP-hydrolysis-dependent manner. Basal expression of PTPA depends on the activity of a ubiquitous transcription factor, Yin Yang 1 (YY1). The tumour suppressor protein p53 can inhibit PTPA expression through an unknown mechanism that negatively controls YY1 [].PTPA as a multihelical structure fold.
Phosphotyrosyl phosphatase activator (PTPA, also known as protein phosphatase 2A activator) proteins stimulate the phosphotyrosyl phosphatase (PTPase) activity of the dimeric form of protein phosphatase 2A (PP2A). PTPase activity in PP2A (in vitro) is relatively low when compared to the better recognised phosphoserine/ threonine protein phosphorylase activity. It also reactivates the serine/threonine phosphatase activity of an inactive form of PP2A. The specific biological role of PTPA is unknown. PTPA has been suggested to play a role in the insertion of metals to the PP2A catalytic subunit (PP2Ac) active site, to act as a chaperone, and more recently, to have peptidyl prolyl cis/trans isomerase activity that specifically targets human PP2Ac [, , , , , ]. Together, PTPA and PP2A constitute an ATPase and it has been suggested that PTPA alters the relative specificity of PP2A from phosphoserine/phosphothreonine substrates to phosphotyrosine substrates in an ATP-hydrolysis-dependent manner. Basal expression of PTPA depends on the activity of a ubiquitous transcription factor, Yin Yang 1 (YY1). The tumour suppressor protein p53 can inhibit PTPA expression through an unknown mechanism that negatively controls YY1 [].PTPA is an α-helical protein which consists of three distinct domains: the core, the linker and the lid. This superfamily consists of the lid domain of PTPA, located usually at the C-terminal.
