Overview:

SIK is a protein kinase that is involved in regulating AMPK-related kinases (1). SIK may mediate the physiological effects of LKB1, including its tumour suppressor function. SIK is also involved in signaling by various proteins like STRAD, NUAK1, NUAK2, BRSK1, BRSK2, QIK, QSK, SIK, MARK1, MARK2, MARK3, MARK4 and MELK that are related to AMPK. Activation of SIK1 by phosphorylation on thr322 can lead to an increase in the catalytic activity of sodium/potassium ATPase alpha subunit at the plasma membrane (2). This results in an increase in intracellular sodium in intact mammalian cells.

References:

1. Takemori, H. Et al: TORC-SIK cascade regulates CREB activity through the basic leucine zipper domain. FEBS J. 2007; 274 (13): 3202–9.

2. Sjostrom, M.; SIK1 is part of a cell sodium-sensing network that regulates active sodium transport through a calcium-dependent process. Proc. Nat. Acad. Sci. 104: 16922-16927, 2007.