Regulation of chondrogenesis by protein kinase C: Emerging new roles in calcium signalling.
During chondrogenesis, complex intracellular signalling pathways regulate an intricate series of events including condensation of chondroprogenitor cells and nodule formation followed by chondrogenic differentiation. Reversible phosphorylation of key target proteins is of particular importance during this process. Among protein kinases known to be involved in these pathways, protein kinase C (PKC) subtypes play pivotal roles. However, the precise function of PKC isoenzymes during chondrogenesis and in mature articular chondrocytes is still largely unclear. In this review, we provide a historical overview of how the concept of PKC-mediated chondrogenesis has evolved, starting from the first discoveries of PKC isoform expression and activity. Signalling components upstream and downstream of PKC, leading to the stimulation of chondrogenic differentiation, are also discussed. Although it is evident that we are only at the beginning to understand what roles are assigned to PKC subtypes during chondrogenesis and how they are regulated, there are many yet unexplored aspects in this area. There is evidence that calcium signalling is a central regulator in differentiating chondroprogenitors; still, clear links between intracellular calcium signalling and prototypical calcium-dependent PKC subtypes such as PKCalpha have not been established. Exploiting putative connections and shedding more light on how exactly PKC signalling pathways influence cartilage formation should open new perspectives for a better understanding of healthy as well as pathological differentiation processes of chondrocytes, and may also lead to the development of novel therapeutic approaches.
Department of Anatomy, Histology and Embryology, Medical and Health Science Centre, University of Debrecen, Nagyerdei krt. 98, H-4032 Debrecen, Hungary. Electronic address: matta.csaba@med.unideb.hu.
Csaba
C
Matta
D-BOARD European Consortium for Biomarker Discovery, Arthritis Research UK Centre for Sport, Exercise and Osteoarthritis, Arthritis Research UK Pain Centre, Medical Research Council and Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Medicine, Faculty of Medicine and Health Sciences, The University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, United Kingdom; School of Pharmacy, University of Bradford, Richmond Road, Bradford BD7 1DP, United Kingdom; School of Life Sciences, University of Bradford, Richmond Road, Bradford BD7 1DP, United Kingdom; Center of Excellence in Genomic Medicine Research (CEGMR), King Abdulaziz University, Jeddah 21589, Saudi Arabia.
Ali
A
Mobasheri
D001168:Arthritis / Q000378:metabolism / Q000473:pathology; D020013:Calcium Signaling; D002356:Cartilage / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000378:metabolism; D019902:Chondrocytes / Q000378:metabolism; D020219:Chondrogenesis; D006801:Humans; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D020033:Protein Isoforms / Q000737:chemistry / Q000378:metabolism; D011493:Protein Kinase C / Q000737:chemistry / Q000378:metabolism*
D015815:Cell Adhesion Molecules; D020033:Protein Isoforms; D011493:Protein Kinase C; D020929:Mitogen-Activated Protein Kinase Kinases
Arthritis; Cartilage; Chondrocyte; Chondrogenesis; Protein kinase C (PKC); Signalling pathway