Activated CDC42 kinase 1, also known as ACK1, is an
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
that in humans is encoded by the ''TNK2''
gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
.
TNK2 gene encodes a non-receptor tyrosine kinase, ACK1, that binds to multiple receptor tyrosine kinases e.g. EGFR, MERTK, AXL, HER2 and insulin receptor (IR). ACK1 also interacts with Cdc42Hs in its GTP-bound form and inhibits both the intrinsic and GTPase-activating protein (GAP)-stimulated GTPase activity of Cdc42Hs. This binding is mediated by a unique sequence of 47 amino acids C-terminal to an SH3 domain. The protein may be involved in a regulatory mechanism that sustains the GTP-bound active form of Cdc42Hs and which is directly linked to a tyrosine phosphorylation signal transduction pathway. Several alternatively spliced transcript variants have been identified from this gene, but the full-length nature of only two transcript variants has been determined.
Interactions
ACK1 or TNK2 has been shown to
interact
Advocates for Informed Choice, dba interACT or interACT Advocates for Intersex Youth, is a 501(c)(3) nonprofit organization using innovative strategies to advocate for the legal and human rights of children with intersex traits. The organizati ...
with
AKT
Protein kinase B (PKB), also known as Akt, is the collective name of a set of three serine/threonine-specific protein kinases that play key roles in multiple cellular processes such as glucose metabolism, apoptosis, cell proliferation, tran ...
,
Androgen receptor or
AR,
a tumor suppressor
WWOX
WW domain-containing oxidoreductase is an enzyme that in humans is encoded by the ''WWOX'' gene.
Function
WW domain-containing proteins are found in all eukaryotes and play an important role in the regulation of a wide variety of cellular func ...
,
FYN
Funen ( da, Fyn, ), with an area of , is the third-largest island of Denmark, after Zealand and Vendsyssel-Thy. It is the 165th-largest island in the world. It is located in the central part of the country and has a population of 469,947 as ...
and
Grb2.
ACK1 interaction with its substrates resulted in their phosphorylation at specific tyrosine residues. ACK1 has been shown to directly phosphorylate AKT at tyrosine 176, AR at Tyrosine 267 and 363, and WWOX at tyrosine 287 residues, respectively. ACK1-AR signaling has also been reported to regulate
ATM levels,
Clinical relevance
ACK1 is a survival kinase and shown to be associated with tumor cell survival, proliferation, hormone-resistance and radiation resistance.
The activation of ACK1 has been observed in prostate, breast, pancreatic, lung and ovarian cancer cells.
ACK1 transgenic mice, expressing activated ACK1 specifically in prostate gland has been reported; these mice develop prostatic intraepithelial neoplasia (PINs).
ACK1 inhibitors
Ack1 has emerged as a new cancer target and multiple small molecule inhibitors have been reported.
All of these inhibitors are currently in the pre-clinical stage.
Mahajan, K., Malla, P., Lawrence, H. R., Chen, Z., Kumar-Sinha, C., Malik, R., … Mahajan, N. P. (2017). ACK1/TNK2 Regulates Histone H4 Tyr88-phosphorylation and AR Gene Expression in Castration-Resistant Prostate Cancer. Cancer Cell, 31(6), 790-803.e8. https://doi.org/10.1016/j.ccell.2017.05.003
Further reading
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External links
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{{Portal bar, Biology, border=no
Tyrosine kinases