Biochemistry and Molecular Biology
Professor of Biochemistry and Molecular Biology Director, Interdisciplinary Training Program in Muscle Biology Marlene and Stewart Greenebaum Comprehensive Cancer Center University of Maryland School of Medicine
Biomedical Research Facility, 215A
Education and Training
I received my Ph.D. from Baylor College of Medicine, Houston, TX in the Department of Cell Biology. After graduating from Baylor College of Medicine, I joined the laboratory of Dr. E.J. Benz, Jr., in the Division of Hematology, Department of Medicine at Johns Hopkins University, School of Medicine in 1998, to study protein 4.1R, a peripheral membrane protein that was originally discovered in red blood cells. In 2001, I moved to the laboratory of Dr. R.J. Bloch, in the Department of Physiology, at the University of Maryland School of Medicine, as an Academic Fellow, to study a small form of ankyrin 1 (small ankyrin 1) that localizes at the sarcoplasmic reticulum membranes, and its ligands in skeletal muscle. In 2002, I was promoted to Research Associate, and 2003 to Research Assistant Professor.
In 2007, I joined the Department of Biochemistry and Molecular Biology at the University of Maryland School of Medicine as Assistant Professor in the tenure track. Using the muscle and epithelial cells as model systems, my laboratory has pioneered the molecular and functional characterization of major cytoskeletal and membrane-associated proteins as structural and signaling mediators in health and disease. My research has been funded by grants from the Muscular Dystrophy Association (MDA), the American Heart Association (AHA) and the National Institutes of Health (NIH).
My research focuses on the elucidation of the roles of cytoskeletal and membrane-associated proteins as structural and signaling mediators. Using the muscle and epithelial cell as model systems, my laboratory has pioneered the molecular and functional characterization of the obscurin subfamily and its binding partner Myosin Binding Protein-C slow in health and disease, ranging from skeletal and cardiac myopathies to breast cancer. As evidence of the recognition of my group for its studies on cytoskeletal regulators, I have been invited to present our work in major national and international meetings, including the American Society for Cell Biology, San Francisco, CA (12/08), the FP7-funded network on Muscle Z-disk Protein Complexes (MUZIC): from Atomic Structure to Physiological Function, Stockholm, Sweden (06/10), The International Society for Heart Research, Baltimore, MD (05/09) and San Diego, CA (06/13), the Experimental Biology Society, San Diego, CA (04/12), the Biophysical Society, Philadelphia, PA (02/13), the Myofilament Meeting, Madison, WI (06/12, 06/14, 05/18), the European Muscle Conference (09/18) etc. In addition, I was invited to organize and chair a symposium in the Experimental Biology Meeting focusing on “Cell Motility in Health and Disease”, San Diego, CA (04/12), and a satellite workshop focusing on “Titin, Obscurin and Myosin Binding Protein-C”, Chicago, IL (06/16). I have also served as Lead Guest Editor in a series of special issues for The Journal of Biotechnology and Biomedicine (2010-2012), Frontiers in Physiology (2013-2014), and The Journal of Muscle Research and Cell Motility (2019-2020) focusing on muscle physiology and pathophysiology.
I have published seventy peer-reviewed articles and contributed two book chapters; in addition, I hold three patents. I have also been serving as reviewer for several journals and study section panels (e.g., National Institutes of Health, American Heart Association, Muscular Dystrophy Association, Cancer Research Foundation, UK, National Cancer Science Center, PL etc.).
To date, I have mentored 10 graduate students, 7 postdoctoral fellows, 1 Fulbright Scholar, and 11 undergraduate students. During my academic career, I have strived to create a comfortable and inclusive lab atmosphere that welcomes diversity. Throughout my individual interactions and group meetings with my trainees, I make it a priority to instill and reinforce the principles and practices of rigorous and reproducible science, including critical review of prior research, careful evaluation of experimental design and data interpretation, consideration of biological variables as well as transparent and accurate reporting of scientific outcomes. As an educator and Director of the Interdisciplinary Training Program in Muscle Biology, my goal is to promote the scientific and personal development of pre- and post-doctoral trainees by providing them with cutting-edge scientific and technological training and a special network of support, mentoring, and interdisciplinary collaborations, which will aid them in developing a successful independent career. As such, one of the proudest moments in my professional life was when I received the 2018 Dr. Patricia Sokolove Outstanding Mentor Award.
Lastly, I am fortunate to have a number of collaborations with prominent scientists in the field of the cytoskeleton within and outside UMSOM, including but not limited to Drs. Martin (UMSOM), Lapidus (UMSOM), Bloch (UMSOM), Ward (UMSOM), Lederer (UMSOM), Weber (UMSOM), Sellers (NHLBI), Bonnemann (NINDS), Sashi (Duke), Konstantopoulos (JHU), Gurnett (Wash U), Ochala (Denmark), & dos Remedios (U Syd, Australia).
cytoskeleton, signaling, skeletal and cardiac muscle (patho)physiology, breast cancer
- Hu, L.-Y. R., Ackermann, M.A., Hecker, P.A., Prosser, B.L., King, B., O’Connell, K., Grogan, A., Meyer, L.C., Berndsen, C.E., Wright, N.T., Lederer, W.J., and Kontrogianni-Konstantopoulos, A.#, “Deregulated Ca2+ cycling underlies the development of arrhythmia and heart disease due to mutant obscurin”, Science Advances, 2017, 3(6):e1603081. doi: 10.1126/sciadv.1603081.
- Hu, LY and Kontrogianni-Konstantopoulos, A#., “The kinase domains of obscurin interact with intercellular adhesion proteins”, FASEB J., 27(5), 2001-2012, 2013. PMCID: PMC3633816.
- Perry, N.A., Shriver, M., Mameza, M.G., Grabias, B., Balzer, E., and Kontrogianni-Konstantopoulos, A.# “Obscurins: Giant Proteins with Tumor Suppressing Activities in Breast Cancer”, FASEB Journal, 26(7), 2764-2775, 2012; PMID: 22441987.
- Shriver, M., Stroka, K.M., Vitolo, M.I., Martin, S.S., Huso, D.L., Konstantopoulos, K., and Kontrogianni-Konstantopoulos A.# “Loss of giant obscurins from breast epithelium promotes epithelial-to-mesenchymal transition, tumorigenicity and metastasis” Oncogene, 2014, doi: 10.1038/onc.2014.358.
- Yankaskas, C., Thompson, K.N., Paul, C.D., Vitolo, M.I., Mistriotis, P., Mahendra, A., Bajpal, V.K., Shea, D.J., Manto, K.M., Chai, A.C., Varadarajan, N., Kontrogianni-Konstantopoulos, A., Martin, S.S., and Konstantopoulos, K. “A microfluidic assay for the quantification of the metastatic propensity of breast-cancer specimens”, Nature Biomedical Engineering, 3(6), 452-465, 2019; doi: 10.1038/s41551-019-0400-9.
- Ackermann, M.A. and Kontrogianni-Konstantopoulos, A.#, “Myosin Binding Protein C Slow is a Novel Substrate for Protein Kinase A (PKA) and C (PKC) in Skeletal Muscle”, Proteome Res., 10(10), 4547-4555, 2011; PMCID: PMC3209537.
- Geist, J., Ward C.W., and Kontrogianni-Konstantopoulos, A.#, “Structure before function: myosin binding protein-C slow is a structural protein with regulatory properties”, FASEB J., DOI: 10.1096/fj.201800624R.
- Stavusis, J., Lace, B., Schäfer, J., Geist, J., Inashkina, I., Kidere, D., Pajusalu, S., Wright, N.T., Saak, A., Weinhold, M., Haubenberger, D., Jackson, S., Kontrogianni-Konstantopoulos#, A., and Bönnemann, C.G.#, “Novel mutations in MYBPC1 are associated with myogenic tremor and mild myopathy”, Ann Neurol, 2019 , doi: 10.1002/ana.25494.
- Shashi, V#., Geist, J., Lee, Y., Yoo, Y., Shin, U., Schoch, J., Sullivan, J., Stong, N., Smith, E., Jasien, J., Kranz, P., Undiagnosed Diseases Network, Lee, Y., Shin, Y.B., Wright, N.T., Choi, M#. and Kontrogianni‐Konstantopoulos, A.#, “Heterozygous variants in MYBPC1 are associated with an expanded neuromuscular phenotype beyond arthrogryposis”, Human Mutation, 2019, DOI: 10.1002/humu.23760.
Honors and Professional Memberships
1988-1990 Award for Excellence in Academic Performance, Institute of National Scholarships, Greece
1993-1994 Graduate Student Scholarship, Department of Cell Biology, Baylor College of Medicine, Houston, Texas
1996 Scholarship Award in Recognition of Excellence in Academic Achievement, Hellenic Professional Society of Texas
1998-1999 Travel Award, American Society of Hematology
1999-2001 National Institute of Health (NIH) Training Grant, Johns Hopkins University, School of Medicine, Division of Hematology, Dept. of Medicine, Baltimore, MD
2000 Research Fellow Investigator Award (one of the five finalists among one hundred and sixty-nine participants), Research Retreat, Johns Hopkins University, School of Medicine, Division of Hematology, Dept. of Medicine, Baltimore, MD
2000-2002 American Heart Association, Mid-Atlantic Post-doctoral Fellowship
2001-2002 National Institute of Health (NIH) Training Grant, University of Maryland Baltimore, School of Medicine, Interdisciplinary Training Program in Muscle Biology
2003-pres. Journal Reviewer
2004-pres. Grant Reviewer (NIH, AHA, NSF, MDA etc.)
2009-2011 Lead Guest Editor, Journal of Biomedicine and Biotechnology; Series of special issues: Advances in Muscle Physiology and Pathophysiology
2010-2018 Interdisciplinary Training Program in Muscle Biology; Member of steering committee
2011 American Society of Cell Biology, Discussion Focus Group
2011-2012 Biophysical Society, Programming Committee
2012 FASEB-Experimental Biology Meeting, Session: Cell Motility in Health and Disease, Chair
2013-2014 Lead Guest Editor, Frontiers in Physiology
2016 Satellite workshop on Titin, Myosin Binding Protein-C and Obscurin; co-Organizer and Moderator, Chicago, IL
2017-pres Scientific Advisory Board Member; European Union Actin cytoskeleton in striated muscle function in Health And Disease-EU AHEAD project (coordinator: Dr. Marie-Louise Bang)
2017-pres Member, Appointments, Promotion & Tenure (APT) Committee, Dept. of Biochemistry and Molecular Biology, UMSOM
2017-pres Scientific Reports: Cell Biology; Editorial Advisory Panel Member
2018 Woman Scientist of the Year, Greece
2018 Dr. Patricia Sokolove Outstanding Mentor Award, University of Maryland Graduate School
2018 Session Chair; European Muscle Conference, Session: Muscle development, regeneration and disease
2018-2019 Co-director; Interdisciplinary Training Program in Muscle Biology
2018-pres. Vice Chair; Heart Failure SFRN Oversight Advisory Committee
2019 Session Chair; 63rd Biophysical Society Meeting, Myosin and skeletal/smooth muscle mechanics, structure and regulation
2019 Session Chair; AHA Basic Cardiovascular Sciences Meeting; Session: Rare genetic diseases in the heart
2019-pres. UMSOM; Preclerkship working group/Curriculum Reform group
2019-2020 NIH-Cardiac Contractility and Heart Failure Study section; Regular member
2019-onwards Director; Interdisciplinary Training Program in Muscle Biology
2019-onwards Member, American Heart Association Research Leaders Academy Planning Committee
2020-2021 Member, Scientific Committee 2nd Olympiad in Cardiovascular Medicine
2020-2022 Member, American Heart Association Basic Cardiovascular Sciences (BCVS) Specialty Conference Program Committee-BCVS Council
2021-2025 NIH-Integrative Muscle Physiology and Pathophysiology-A Study Section; Chair & Regular Member
- R01AR076373 (Kontrogianni-Konstantopoulos, A.)
“Novel MYBPC1 mutations cosegregate with a myopathy associated with muscle weakness, hypotonia and tremor”
- R01AR077106 (Kontrogianni-Konstantopoulos, A & Bloch, RJ, Multi-PI)
“Cytoskeletal regulation of SERCA in muscle”
- Research Grant (Kontrogianni-Konstantopoulos, A.)
Muscular Dystrophy Association 02/01/19-01/31/22
“Novel mutations in MYBPC1 resulting in myopathy with tremor”
- T32 AR007592 (Kontrogianni-Konstantopoulos, A.; Program Director since 07/19) NIH/NIAMS 05/01/96-04/30/26
“Interdisciplinary Training Program in Muscle Biology”
Contributions to Science
General note on our research focusing on the giant cytoskeletal proteins obscurins: Studying the biology of obscurins has presented us with many challenges due to their apparent large size (500-920 kDa), multifaceted nature and unique biochemical properties. Consequently, during the last ~20 years that the OBSCN gene encoding obscurins has been identified, we have developed an arsenal of experimental protocols and methodologies and generated a plethora of reagents, including a panel of highly specific antibodies, small inhibitory RNA plasmids, adenoviral overexpression vectors, and more recently deletion and knock-in models.
Below please see three major areas of research on obscurins that we are currently pursuing.
1. Obscurin in heart pathophysiology
Giant obscurins are multidomain proteins expressed in striated muscles that intimately surround sarcomeres at the level of M-bands and Z-disks. Manipulation of the expression levels of obscurins, either in vitro or in vivo, has shown that they play key roles in myofibrillogenesis, the cytoskeletal alignment of the SR membranes, and the subsarcolemmal organization of microtubules, highlighting their importance in striated muscle structure and function. This is further highlighted by the identification of mutations in the OBSCN gene that are directly linked to the development of hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM) and left ventricular noncompaction (LVNC) in humans. To study the roles of obscurins in cardiac pathophysiology, my laboratory has generated knock-in and deletion mouse models expressing mutant obscurins that carry disease-associated mutations and truncated obscurins that lack binding modules, respectively. Our studies indicate a direct involvement of obscurins in Ca2+ cycling through the regulation of SERCA activity and mechanotransduction pathways through their interaction with titins. Our research focuses on the detailed mechanistic characterization of the molecular, biochemical, and cellular alterations taking placing in myocardia and skeletal muscles expressing mutant or truncated obscurins.
2. Obscurin-Kinase Activity at the Intercalated Disc
Two main isoforms of obscurin have been characterized to date, obscurin A (~720 kDa) and obscurin B (~870 kDa). These share the same NH2-terminal adhesion and signaling motifs but have unique COOH-termini. While obscurin A contains a non-modular COOH-terminus, obscurin B contains two Ser/Thr kinase domains, referred to as Kin1 and Kin2 that belong to the myosin light chain kinase (MLCK) family. Contrary to obscurin A, obscurin B is also present at the intercalated disk (ICD), the unique microdomain of the sarcolemma that contributes to the mechanical and electrochemical coupling of neighboring cardiomyocytes. Consistent with this, the transcript levels of obscurin B dramatically increase in response to aortic stenosis and tachycardia. Although the presence of Kin1 and Kin2 in obscurin B was discovered more than a decade ago, their enzymatic activity, catalytic substrates and (patho)physiological roles have remained elusive. It is only recently that our group demonstrated that both Kin1 and Kin2 are enzymatically active. In particular, Kin1 undergoes autophosphorylation, and directly binds to and phosphorylates the cytoplasmic domain of N-cadherin. N-cadherin is a major component of the ICD that plays pivotal roles in maintaining the structural integrity and synchronous beating of the myocardium. Our research aims to show that the obscurin Kin1 domain plays key roles in cell-cell adhesion and communication in cardiac muscle by regulating the activities of N-cadherin via phosphorylation of its cytoplasmic domain. Given the involvement of obscurins in cardiac (patho)physiology, the pivotal roles of MLCK/MLCK-like kinases in cardiac structure & function, and the development of severe and lethal cardiomyo-pathies due to deregulated ICD proteins, our studies are of high (patho)physiological significance and relevance.
3. Giant Obscurins in Breast Cancer Development and Metastasis
Recent evidence has unexpectedly implicated OBSCN in cancer development due to the high mutational prevalence it exhibits in different types of cancer, including breast cancer, leading to significant reduction of the obscurin transcript levels. In light of this observation, we began to unravel the roles of the OBSCN gene in breast cancer formation and progression1-3. Our studies were the first to show that giant obscurins are abundantly expressed in normal breast tissue but are virtually absent from advanced stage human breast cancer biopsies. Normal breast epithelial cells depleted of giant obscurins exhibit dramatically increased survival, motility and invasiveness. Consistent with these findings, obscurin-knockdown (KD) breast epithelial cells fail to form adherens junctions and undergo Epithelial to Mesenchymal Transition (EMT). More importantly, obscurin-KD, but not scramble control, breast epithelial cells expressing an active form of K-Ras form extensive local (primary) tumors and lung metastases in vivo. We thus hypothesize that loss of giant obscurins correlates with the tumorigenic and metastatic propensity of breast tumors, and propose to establish giant obscurins (or lack thereof) as a novel prognostic biomarker for metastatic breast cancer, and to elucidate the molecular and cellular alterations due to their loss. More importantly, restoration of the expression and/or functionality of obscurins in obscurin-deficient breast cancer cells using genome editing and peptide therapy approaches are major goals of my lab. Thus, our research has important clinical implications in the establishment of obscurin as novel prognostic biomarker for metastatic breast cancer and the development of new, more effective, targeted therapies.
General note on our research focusing on the Myosin Binding Protein-C Slow (MyBP-C slow) subfamily: We originally identified MyBP-C slow as a binding partner of giant obscurins in skeletal muscle1. Given the molecular complexity, differential phosphorylation, key structural and regulatory roles, and direct involvement of MyBP-C slow in Distal Arthrogryposis and a new form of distal myopathy characterized by muscle weakness and tremor, the biology of the MyBP-C slow subfamily has become a major project in my laboratory.
4. MyBP-C Slow: a Multifaceted Regulator of Muscle Structure and Function
Myosin Binding Protein-C (MyBP-C) comprises a subfamily of thick filament associated proteins that has structural and regulatory roles. Three distinct isoforms have been characterized, including the cardiac (c), slow skeletal (s) and fast skeletal (f). During the last forty years, numerous studies have focused on elucidating the mechanisms that modulate the activities of cMyBP-C. On the contrary, the regulation and roles of the skeletal isoforms have remained obscure, and mainly inferred due to the structural similarity they share with cMyBP-C. Our group has been studying the slow skeletal form of MyBP-C aiming to understand its regulation and activities1-5. Using molecular tools, we have shown that the MYBPC1 gene, encoding sMyBP-C, is heavily spliced giving rise to several variants, which are expressed in different combinations and amounts during development and in adulthood, in both slow- and fast-twitch skeletal muscles. The slow variants share common domains but differ by the inclusion or skipping of novel insertions located in the NH2-terminus, the FN-III C7 domain and the COOH-terminus. Both the NH2 and COOH termini can retain native myosin and actin and modulate the sliding velocity of actin filaments past myosin heads, though to different extents, and in a variant-specific manner. Moreover, using proteomic tools, we have demonstrated that sMyBP-C undergoes extensive phosphorylation mediated by PKA and PKC. In particular, we have identified four phosphorylation sites in the NH2-terminus of the protein, with one of them located within an alternatively spliced region. Recently, mutations in MYBPC1 slow were directly associated with the development of different forms of arthrogryposis: Distal Arthrogryposis Type 1 and 2 (DA1 and DA2), which are severe autosomal dominant disorders that selectively affect the distal limbs, Lethal Congenital Contractural Syndrome Type 4 (LCCS4), a neonatal lethal autosomal recessive syndrome, and a novel distal myopathy accompanied by muscle weakness, hypotonia, tremor and facial/body deformities. We therefore propose that sMyBP-C plays important structural and regulatory roles in developing and adult skeletal muscles via the expression of distinct variants that are differentially phosphorylated. Our goals are to delineate the roles and regulation of sMyBP-C during myofibrillogenesis and in adulthood in both slow and fast twitch muscles, and to examine how these are compromised in disease.