Ubiquitin-associated domain of MARK4 provides stability at physiological pH.
Microtubule affinity regulating Kinase 4 (MARK4) belongs to the family of AMP-activated protein kinase. It phosphorylates microtubule associated proteins at specific sites (Serine in KXGS motifs) in the microtubule-binding repeats. In our previous studies, two constructs, namely, kinase domain with 59 N-terminal residues (residues 1-310) and only kinase domain (residues 59-310) of MARK4 show aggregation at physiological pH. However, these two constructs were stable at extremes of pH conditions. Now the question arises: how is MARK4 stable at physiological pH in-vivo? To answer this question, we have successfully cloned, expressed, and purified UBA-domain along with the kinase domain of MARK4 and performed spectroscopic measurements and activity assays. We observed a pronounced secondary and tertiary structure and ATPase activity in the MARK4 at physiological pH. In conclusion, UBA domain may be important to maintain the structure, stability and activity of MARK4 under physiological conditions.
Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India.
Farha
F
Naz
Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India.
Neha
N
Sami
Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India.
Asimul
A
Islam
Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India.
Faizan
F
Ahmad
Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India. Electronic address: imtiyaz.hassan@gmail.com.
Md Imtaiyaz
MI
Hassan
D000251:Adenosine Triphosphatases / Q000378:metabolism; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D000072417:Protein Domains; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000378:metabolism*; D017433:Protein Structure, Secondary; D014452:Ubiquitins / Q000378:metabolism*
D014452:Ubiquitins; D017346:Protein Serine-Threonine Kinases; D000251:Adenosine Triphosphatases
ATPase activity; Microtubule affinity-regulating kinase 4; Protein aggregation; Protein folding; Protein stability; UBA domain