Table 1 Protein-modifying enzymes and their targets at the Saccharomyces cerevisiae bud neck

Protein kinases

Cbk1

NDR2

NDR family; cell wall morphogenesis, cell separation

Ace2

[79]

Cdc5

PLK2

Polo/PLK family; cell cycle regulation, cytokinesis, mitotic exit

Swe1

[80]

Cdc15

MST1

STE20-like family; activated by GTP-bound Tem1, late nuclear division, mitotic exit

Dbf2

[81]

Cdc28

CDK1

Catalytic subunit of Cdk1; cell cycle progression

Cdc3

Shs1

Swe1

[48, 50, 82]

Clb2

Cyclin B2

B-type cyclin; regulatory subunit for Cdc28; cell cycle progression

---

[83]

Dbf2

Dbf20

LATS1

NDR family; anaphase-telophase, mitotic exit

Cdc14

[84]

Elm1

LKB1

Upstream activator of Snf1 and other AMPK-like protein kinases involved in septin assembly

Gin4

Hsl1

Kcc4

[85, 86]

Gin4

BRSK1

Nim1-related and AMPK-like family; septin collar assembly

Shs1

Swe1?

[49]

Hrr25

CKIδ

Casein kinase I family; located throughout the cell, but concentrated at bud tip and bud neck

?

[87]

Hsl1

BRSK2

Nim1-related and AMPK-like family; morphogenesis checkpoint, Swe1 degradation

Shs1

Swe1

Trott AE, Gullbrand B & Thorner J, unpublished results

Kcc4

BRSK1

Nim1-related and AMPK-like family; septin collar assembly

Swe1?

[88]

Kin4

MARK4

AMPK-like family; negatively regulates mitotic exit in response to a misaligned spindle

Gic2?

Hsl1?

[89, 90]

Mob1

MATS1

Regulatory and substrate targeting subunit of Dbf2 (and Dbf20)

---

[91]

Mob2

MOB1A

Regulatory and substrate targeting subunit of Cbk1

---

[91]

Pcl1

Pcl2

Pcl9

Cyclin A/B

AB-type cyclins; regulatory subunits for Pho85; cell morphogenesis

---

[92–94]

Pho85

CDK5

Catalytic subunit; transcription, cell morphogenesis

Bni4

Cdc3

Cdc10

Cdc12

[33, 95]

Pkc1

PRK2

Cell wall integrity; activated by GTP-bound Rho1, localizes to bud neck late in the cell cycle before cell separation

?

[96]

Rad53

CHK2

DNA damage checkpoint

Shs1

Cdc12

[97]

Swe1

WEE1

Morphogenesis checkpoint

Cdc28

[98]

Yck2

CKIγ

Casein kinase I family; a peripheral plasma membrane protein anchored by C-terminal palmitoylation

?

[99]

Phosphatases

Afr1

PHACTR4

Regulatory and substrate targeting subunit of phosphoprotein phosphatase (PP) 1; septin reorganization during mating projection formation

---

[100]

Cdc55

B55β2

B-type regulatory and substrate targeting subunit of PP2A

---

[101]

Glc7

PP1

Catalytic subunit of PP1

?

[102]

Pph21

Pph22

PP2ACα

PP2ACβ

Catalytic subunit isoforms of PP2A

?

[101, 103]

Rts1

B56δ1

B'-type regulatory and substrate targeting subunit of PP2A

Shs1

[53]

Tpd3

PR65α

A-type regulatory (scaffold) subunit of PP2A

---

[103]

Other modifiers

Grr1

FBXL20

F-box protein for substrate recognition by an SCF (Skp1—Cdc53—Cdc34)-type ubiquitin-protein ligase (E3), targets landmark proteins for destruction after septin ring site is established

Gic1?

Gic2

[104, 105]

Hsl7

JBP1

PRMT5; type II protein-arginine methyltransferase that generates symmetric N, N'-dimethylarginine residues in its substrates

Swe1?

[106, 107]

Siz1

Siz2/Nfi1

PIAS2

PIAS4

RING-like domain-containing SUMO-protein ligases (E3); responsible for mother side-specific attachment of SUMO to septins in the collar at the neck at the onset of anaphase

Cdc3

Cdc11

Shs1

[61, 76]

Mms21

-none-

U box domain-containing SUMO-protein ligase (E3); capable of attaching SUMO to septins when Siz1 & Siz2 absent

Cdc3

Cdc11

Shs1

[63]

Smt3

SUMO-1

Small ubiquitin-like modifier; may contribute to regulating disassembly of septin collar and/or association of other proteins with septins in the collar

---

[108]